I want to write a browser (Chrome/FF) extension that needs to select an element on a web page. I would like it to behave like Firebug's element inspector does. You click the inspect arrow and you can then hover/highlight elements. When you click on the element you want, the element is inspected. I'm just interested in the code to allow a user to select an element - not in actually inspecting it or anything similar.
Because I'm writing an extension, it might be nice if you could provide non-jQuery/Prototype/etc.. code so I don't have to distribute that.
I have recently required such a feature for a project I was working on, turned out that I had to use for sides to create a box because otherwise the event.target when you move the mouse would end up being the selector, and if I were to use z-index: -1 it would be a bit fishy when you have a lot of elements that overlap...etc.
Here is a version that I have converted from my project for your benefit, it involves jQuery but it is extremely simple to convert to vanilla as only the mousemove & css methods from jQuery are used.
Step by step instructions.
First create the 5 HTMLElements that are required.
<div id="selector">
<div id="selector-top"></div>
<div id="selector-left"></div>
<div id="selector-right"></div>
<div id="selector-bottom"></div>
</div>
Secondly create a mousemove event on the document (or your container)
$(document).mousemove(function(event) { ... });
Then inside the mousemove we will do some basic checking to prevent selecting the HTML, BODY, selector
var id = event.target.id, tagName = event.target.tagName;
if(id.indexOf('selector') !== -1 || tagName === 'BODY' || tagName === 'HTML') {
return;
}
Then we need to create a object to store our elements like so.
var elements = {
top: $('#selector-top'),
left: $('#selector-left'),
right: $('#selector-right'),
bottom: $('#selector-bottom')
};
After that we store some variables that hold some information about the target element like so.
var $target = event.target;
targetOffset = $target.getBoundingClientRect(),
targetHeight = targetOffset.height,
targetWidth = targetOffset.width;
Then all we do is calculate the position & height for all 4 sides of the selector like so.
elements.top.css({
left: (targetOffset.left - 4),
top: (targetOffset.top - 4),
width: (targetWidth + 5)
});
elements.bottom.css({
top: (targetOffset.top + targetHeight + 1),
left: (targetOffset.left - 3),
width: (targetWidth + 4)
});
elements.left.css({
left: (targetOffset.left - 5),
top: (targetOffset.top - 4),
height: (targetHeight + 8)
});
elements.right.css({
left: (targetOffset.left + targetWidth + 1),
top: (targetOffset.top - 4),
height: (targetHeight + 8)
});
All of the +aFewPixels is just a little optimization so that there is like 2px gap in between the selector and the target.
For the CSS this is what I have come up with.
#selector-top, #selector-bottom {
background: blue;
height:3px;
position: fixed;
transition:all 300ms ease;
}
#selector-left, #selector-right {
background: blue;
width:3px;
position: fixed;
transition:all 300ms ease;
}
The transition gives the selector a very nice sliding effect.
Try out a demo http://jsfiddle.net/rFc8E/9/
Note: This also works for transform: scale(2); eg. when a element is scaled in size.
Edit: I've just updated this, I noticed that the elements object was inside the event handler, I've moved it outside in the demo, this is quite an important performance improvement because now, the elements object is only created once instead of Hundreds of Thousands if not millions of times inside the mousemove event.
I wrote an implementation of this using jQuery as a component of another project. The source and documentation are available here: https://github.com/andrewchilds/jQuery.DomOutline
One simple way to do it is to use an outline instead of a border:
.highlight { outline: 4px solid #07C; }
Just add and remove that class to any element you want to select/deselect (code below is not properly tested):
document.body.addEventListener("mouseover", function(e) {
e.stopPropagation();
e.target.addEventListener("mouseout", function (e) {
e.target.className = e.target.className.replace(new RegExp(" highlight\\b", "g"), "");
});
e.target.className += " highlight";
});
Since you are using an outline, (which is supported by Chrome) instead of a border, elements will not jump around. I'm using something similar in my EasyReader Extension.
HTML Element Picker (Vanilla JS)
Pick and highlight any HTML element on a page with only Vanilla JS! Tested in Chrome, FF, and Opera, doesn't work in IE.
How it works:
What you need is actually very simple. You can just create an empty div box with a background in JS and move it around to highlight on top of hovered elements.
Here's the JS code:
const hoverBox = document.createElement("div");
console.log("hoverBox: ", hoverBox);
hoverBox.style.position = "absolute";
// change to whatever highlight color you want
hoverBox.style.background = "rgba(153, 235, 255, 0.5)";
// avoid blocking the hovered element and its surroundings
hoverBox.style.zIndex = "0";
document.body.appendChild(hoverBox);
let previousTarget;
document.addEventListener("mousemove", (e) => {
let target = e.target;
if (target === hoverBox) {
// the truely hovered element behind the added hover box
const hoveredElement = document.elementsFromPoint(e.clientX, e.clientY)[1];
if (previousTarget === hoveredElement){
// avoid repeated calculation and rendering
return;
} else{
target = hoveredElement;
}
} else{
previousTarget = target;
}
const targetOffset = target.getBoundingClientRect();
const targetHeight = targetOffset.height;
const targetWidth = targetOffset.width;
// add a border around hover box
const boxBorder = 5;
hoverBox.style.width = targetWidth + boxBorder * 2 + "px";
hoverBox.style.height = targetHeight + boxBorder * 2 + "px";
// need scrollX and scrollY to account for scrolling
hoverBox.style.top = targetOffset.top + window.scrollY - boxBorder + "px";
hoverBox.style.left = targetOffset.left + window.scrollX - boxBorder + "px";
});
See Demo
I also made an npm package for the element picker with many more user configurations like background color, border width, transition, etc.
Here's the GitHub page.
I ended up asking in the Firebug group and got some great help:
http://groups.google.com/group/firebug/browse_thread/thread/7d4bd89537cd24e7/2c9483d699efe257?hl=en#2c9483d699efe257
Here is a library that written in pure javascript as an alternative.
TheRoom JS: https://github.com/hsynlms/theroomjs
// theroom information template for target element
var template="";
template += "<div id=\"theroom-info\">";
template += " <span id=\"theroom-tag\"><\/span>";
template += " <span id=\"theroom-id\"><\/span>";
template += " <span id=\"theroom-class\"><\/span>";
template += "<\/div>";
template += "";
template += "<style>";
template += " #theroom-info {";
template += " position: fixed;";
template += " bottom: 0;";
template += " width: 100%;";
template += " left: 0;";
template += " font-family: \"Courier\";";
template += " background-color: #ffffff;";
template += " padding: 10px;";
template += " color: #333333;";
template += " text-align: center;";
template += " box-shadow: 0px 4px 20px rgba(0,0,0,0.3);";
template += " }";
template += "";
template += " #theroom-tag {";
template += " color: #C2185B;";
template += " }";
template += "";
template += " #theroom-id {";
template += " color: #5D4037;";
template += " }";
template += "";
template += " #theroom-class {";
template += " color: #607D8B;";
template += " }";
template += "<\/style>";
var options = {
template: template,
showInfo: true
};
// initialize
theRoom.start(options);
codepen demo
There was a similar question asked on Stackoverflow and it had lots of good answers:
Does anyone know a DOM inspector javascript library or plugin?
For those who are looking for a quick and dirty solution:
http://userscripts.org/scripts/review/3006 is the easiest. Just put the code within <script></script> tags and you are good to go.
https://github.com/josscrowcroft/Simple-JavaScript-DOM-Inspector/blob/master/inspector.js is slightly better and still very easy to integrate in.
For a more sophisticated element inspector, you might want to check out the SelectorGadget as pointed by Udi. The inspector selection code is in http://www.selectorgadget.com/stable/lib/interface.js
Also check this one out:
http://rockingcode.com/tutorial/element-dom-tree-jquery-plugin-firebug-like-functionality/
I found it pretty insightful.. and there's a demo here:
http://rockingcode.com/demos/elemtree/
Hope this helps.
A very basic implementation can be done very easily without jQuery using .onmouseover and e.target:
var last,
bgc;
document.onmouseover = function(e) {
var elem = e.target;
if (last != elem) {
if (last != null) {
last.classList.remove("hovered");
}
last = elem;
elem.classList.add("hovered");
}
}
With the CSS below if you want the children to change background as well:
.hovered,
.hovered * {
cursor: pointer;
color: black;
background-color: red;
}
Demo
If you want to select elements only near the edges (or select the parent near the edges and the element itself everywhere else) you could use .getBoundingClientRect.
var last;
window.addEventListener("mousemove", function(e) {
if(last) {
last.style.background = ''; // empty is enough to restore previous value
}
var elem = e.target;
if(elem === document.body || elem === document.documentElement) {
return;
}
var bb = elem.getBoundingClientRect();
var xr = e.pageX - bb.left; // x relative to elem
var yr = e.pageY - bb.top; // y relative to elem
var ew = 10; // edge width
if(
xr <= ew
|| xr >= bb.width - ew
|| yr <= ew
|| yr >= bb.height - ew
){
elem.style.background = 'red';
last = elem;
}
});
Paired with some borders, this can be pretty usable for selection. Demo
What you need to do is to create 4 elements for the highlighting. They will form an empty square, and so your mouse events are free to fire. This is similar to this overlay example I've made.
The difference is that you only need the four elements (no resize markers), and that the size and position of the 4 boxes are a bit different (to mimick the red border). Then you can use event.target in your event handler, because it gets the real topmost element by default.
Another approach is to hide the exra element, get elementFromPoint, calculate then put it back.
They're faster than light, I can tell you. Even Einstein would agree :)
1.) elementFromPoint overlay/borders - [Demo1] FF needs v3.0+
var box = $("<div class='outer' />").css({
display: "none", position: "absolute",
zIndex: 65000, background:"rgba(255, 0, 0, .3)"
}).appendTo("body");
var mouseX, mouseY, target, lastTarget;
// in case you need to support older browsers use a requestAnimationFrame polyfill
// e.g: https://gist.github.com/paulirish/1579671
window.requestAnimationFrame(function frame() {
window.requestAnimationFrame(frame);
if (target && target.className === "outer") {
box.hide();
target = document.elementFromPoint(mouseX, mouseY);
}
box.show();
if (target === lastTarget) return;
lastTarget = target;
var $target = $(target);
var offset = $target.offset();
box.css({
width: $target.outerWidth() - 1,
height: $target.outerHeight() - 1,
left: offset.left,
top: offset.top
});
});
$("body").mousemove(function (e) {
mouseX = e.clientX;
mouseY = e.clientY;
target = e.target;
});
2.) mouseover borders - [Demo2]
var box = new Overlay();
$("body").mouseover(function(e){
var el = $(e.target);
var offset = el.offset();
box.render(el.outerWidth(), el.outerHeight(), offset.left, offset.top);
});
/**
* This object encapsulates the elements and actions of the overlay.
*/
function Overlay(width, height, left, top) {
this.width = this.height = this.left = this.top = 0;
// outer parent
var outer = $("<div class='outer' />").appendTo("body");
// red lines (boxes)
var topbox = $("<div />").css("height", 1).appendTo(outer);
var bottombox = $("<div />").css("height", 1).appendTo(outer);
var leftbox = $("<div />").css("width", 1).appendTo(outer);
var rightbox = $("<div />").css("width", 1).appendTo(outer);
// don't count it as a real element
outer.mouseover(function(){
outer.hide();
});
/**
* Public interface
*/
this.resize = function resize(width, height, left, top) {
if (width != null)
this.width = width;
if (height != null)
this.height = height;
if (left != null)
this.left = left;
if (top != null)
this.top = top;
};
this.show = function show() {
outer.show();
};
this.hide = function hide() {
outer.hide();
};
this.render = function render(width, height, left, top) {
this.resize(width, height, left, top);
topbox.css({
top: this.top,
left: this.left,
width: this.width
});
bottombox.css({
top: this.top + this.height - 1,
left: this.left,
width: this.width
});
leftbox.css({
top: this.top,
left: this.left,
height: this.height
});
rightbox.css({
top: this.top,
left: this.left + this.width - 1,
height: this.height
});
this.show();
};
// initial rendering [optional]
// this.render(width, height, left, top);
}
Related
I want to know how to get the X and Y position of HTML elements such as img and div in JavaScript.
The correct approach is to use element.getBoundingClientRect():
var rect = element.getBoundingClientRect();
console.log(rect.top, rect.right, rect.bottom, rect.left);
Internet Explorer has supported this since as long as you are likely to care about and it was finally standardized in CSSOM Views. All other browsers adopted it a long time ago.
Some browsers also return height and width properties, though this is non-standard. If you're worried about older browser compatibility, check this answer's revisions for an optimised degrading implementation.
The values returned by element.getBoundingClientRect() are relative to the viewport. If you need it relative to another element, simply subtract one rectangle from the other:
var bodyRect = document.body.getBoundingClientRect(),
elemRect = element.getBoundingClientRect(),
offset = elemRect.top - bodyRect.top;
alert('Element is ' + offset + ' vertical pixels from <body>');
This function returns an element's position relative to the whole document (page):
function getOffset(el) {
const rect = el.getBoundingClientRect();
return {
left: rect.left + window.scrollX,
top: rect.top + window.scrollY
};
}
Using this we can get the X position:
getOffset(element).left
... or the Y position:
getOffset(element).top
The libraries go to some lengths to get accurate offsets for an element.
here's a simple function that does the job in every circumstances that I've tried.
function getOffset( el ) {
var _x = 0;
var _y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
_x += el.offsetLeft - el.scrollLeft;
_y += el.offsetTop - el.scrollTop;
el = el.offsetParent;
}
return { top: _y, left: _x };
}
var x = getOffset( document.getElementById('yourElId') ).left;
If you want it done only in javascript, here are some one liners using getBoundingClientRect()
window.scrollY + document.querySelector('#elementId').getBoundingClientRect().top // Y
window.scrollX + document.querySelector('#elementId').getBoundingClientRect().left // X
The first line will return offsetTop say Y relative to document.
The second line will return offsetLeft say X relative to document.
getBoundingClientRect() is a javascript function that returns the position of the element relative to viewport of window.
HTML elements on most browsers will have:-
offsetLeft
offsetTop
These specifiy the position of the element relative its nearest parent that has layout. This parent can often be accessed bif the offsetParent property.
IE and FF3 have
clientLeft
clientTop
These properties are less common, they specify an elements position with its parents client area (padded area is part of the client area but border and margin is not).
If page includes - at least- any "DIV", the function given by meouw throws the "Y" value beyond current page limits. In order to find the exact position, you need to handle both offsetParent's and parentNode's.
Try the code given below (it is checked for FF2):
var getAbsPosition = function(el){
var el2 = el;
var curtop = 0;
var curleft = 0;
if (document.getElementById || document.all) {
do {
curleft += el.offsetLeft-el.scrollLeft;
curtop += el.offsetTop-el.scrollTop;
el = el.offsetParent;
el2 = el2.parentNode;
while (el2 != el) {
curleft -= el2.scrollLeft;
curtop -= el2.scrollTop;
el2 = el2.parentNode;
}
} while (el.offsetParent);
} else if (document.layers) {
curtop += el.y;
curleft += el.x;
}
return [curtop, curleft];
};
You can add two properties to Element.prototype to get the top/left of any element.
Object.defineProperty( Element.prototype, 'documentOffsetTop', {
get: function () {
return this.offsetTop + ( this.offsetParent ? this.offsetParent.documentOffsetTop : 0 );
}
} );
Object.defineProperty( Element.prototype, 'documentOffsetLeft', {
get: function () {
return this.offsetLeft + ( this.offsetParent ? this.offsetParent.documentOffsetLeft : 0 );
}
} );
This is called like this:
var x = document.getElementById( 'myDiv' ).documentOffsetLeft;
Here's a demo comparing the results to jQuery's offset().top and .left: http://jsfiddle.net/ThinkingStiff/3G7EZ/
To retrieve the position relative to the page efficiently, and without using a recursive function: (includes IE also)
var element = document.getElementById('elementId'); //replace elementId with your element's Id.
var rect = element.getBoundingClientRect();
var elementLeft,elementTop; //x and y
var scrollTop = document.documentElement.scrollTop?
document.documentElement.scrollTop:document.body.scrollTop;
var scrollLeft = document.documentElement.scrollLeft?
document.documentElement.scrollLeft:document.body.scrollLeft;
elementTop = rect.top+scrollTop;
elementLeft = rect.left+scrollLeft;
How about something like this, by passing ID of the element and it will return the left or top, we can also combine them:
1) find left
function findLeft(element) {
var rec = document.getElementById(element).getBoundingClientRect();
return rec.left + window.scrollX;
} //call it like findLeft('#header');
2) find top
function findTop(element) {
var rec = document.getElementById(element).getBoundingClientRect();
return rec.top + window.scrollY;
} //call it like findTop('#header');
or 3) find left and top together
function findTopLeft(element) {
var rec = document.getElementById(element).getBoundingClientRect();
return {top: rec.top + window.scrollY, left: rec.left + window.scrollX};
} //call it like findTopLeft('#header');
Here's a modern 1-liner using vanilla JS to recursively iterate over element.offsetTop and element.offsetParent:
Function:
getTop = el => el.offsetTop + (el.offsetParent && getTop(el.offsetParent))
Usage:
const el = document.querySelector('#div_id');
const elTop = getTop(el)
Advantage:
Always returns the absolute vertical offset, regardless of the current scroll position.
Traditional syntax:
function getTop(el) {
return el.offsetTop + (el.offsetParent && getTop(el.offsetParent));
}
jQuery .offset() will get the current coordinates of the first element, or set the coordinates of every element, in the set of matched elements, relative to the document.
Update:
The recursion approach (in my old answer) creates many call stacks. We can use a while loop to avoid recursion in this case:
/**
*
* #param {HTMLElement} el
* #return {{top: number, left: number}}
*/
function getDocumentOffsetPosition(el) {
let top = 0, left = 0;
while (el !== null) {
top += el.offsetTop;
left += el.offsetLeft;
el = el.offsetParent;
}
return {top, left};
}
Old answer:
/**
*
* #param {HTMLElement} el
* #return {{top: number, left: number}}
*/
function getDocumentOffsetPosition(el) {
var position = {
top: el.offsetTop,
left: el.offsetLeft
};
if (el.offsetParent) {
var parentPosition = getDocumentOffsetPosition(el.offsetParent);
position.top += parentPosition.top;
position.left += parentPosition.left;
}
return position;
}
Thank ThinkingStiff for the answer, this is only another version.
You might be better served by using a JavaScript framework, that has functions to return such information (and so much more!) in a browser-independant fashion. Here are a few:
Prototype
jQuery
MooTools
YUI (yahoo)
With these frameworks, you could do something like:
$('id-of-img').top
to get the y-pixel coordinate of the image.
I've taken #meouw's answer, added in the clientLeft that allows for the border, and then created three versions:
getAbsoluteOffsetFromBody - similar to #meouw's, this gets the absolute position relative to the body or html element of the document (depending on quirks mode)
getAbsoluteOffsetFromGivenElement - returns the absolute position relative to the given element (relativeEl). Note that the given element must contain the element el, or this will behave the same as getAbsoluteOffsetFromBody. This is useful if you have two elements contained within another (known) element (optionally several nodes up the node tree) and want to make them the same position.
getAbsoluteOffsetFromRelative - returns the absolute position relative to the first parent element with position: relative. This is similar to getAbsoluteOffsetFromGivenElement, for the same reason but will only go as far as the first matching element.
getAbsoluteOffsetFromBody = function( el )
{ // finds the offset of el from the body or html element
var _x = 0;
var _y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) )
{
_x += el.offsetLeft - el.scrollLeft + el.clientLeft;
_y += el.offsetTop - el.scrollTop + el.clientTop;
el = el.offsetParent;
}
return { top: _y, left: _x };
}
getAbsoluteOffsetFromGivenElement = function( el, relativeEl )
{ // finds the offset of el from relativeEl
var _x = 0;
var _y = 0;
while( el && el != relativeEl && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) )
{
_x += el.offsetLeft - el.scrollLeft + el.clientLeft;
_y += el.offsetTop - el.scrollTop + el.clientTop;
el = el.offsetParent;
}
return { top: _y, left: _x };
}
getAbsoluteOffsetFromRelative = function( el )
{ // finds the offset of el from the first parent with position: relative
var _x = 0;
var _y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) )
{
_x += el.offsetLeft - el.scrollLeft + el.clientLeft;
_y += el.offsetTop - el.scrollTop + el.clientTop;
el = el.offsetParent;
if (el != null)
{
if (getComputedStyle !== 'undefined')
valString = getComputedStyle(el, null).getPropertyValue('position');
else
valString = el.currentStyle['position'];
if (valString === "relative")
el = null;
}
}
return { top: _y, left: _x };
}
If you are still having problems, particularly relating to scrolling, you could try looking at http://www.greywyvern.com/?post=331 - I noticed at least one piece of questionable code in getStyle which should be fine assuming browsers behave, but haven't tested the rest at all.
Difference between small and little
function getPosition( el ) {
var x = 0;
var y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
x += el.offsetLeft - el.scrollLeft;
y += el.offsetTop - el.scrollTop;
el = el.offsetParent;
}
return { top: y, left: x };
}
Look a example coordinates:
http://javascript.info/tutorial/coordinates
If you are using jQuery, this could be a simple solution:
<script>
var el = $("#element");
var position = el.position();
console.log( "left: " + position.left + ", top: " + position.top );
</script>
if using jQuery, the dimensions plugin is excellent and allows you specify exactly what you want.
e.g.
Relative position, absolute position, absolute position without padding, with padding...
It goes on, let's just say there is a lot you can do with it.
Plus the bonus of using jQuery is it's lightweight file size and easy use, you won't go back to JavaScript without it afterwards.
The cleanest approach I have found is a simplified version of the technique used by jQuery's offset. Similar to some of the other answers it starts with getBoundingClientRect; it then uses the window and the documentElement to adjust for scroll position as well as things like the margin on the body (often the default).
var rect = el.getBoundingClientRect();
var docEl = document.documentElement;
var rectTop = rect.top + window.pageYOffset - docEl.clientTop;
var rectLeft = rect.left + window.pageXOffset - docEl.clientLeft;
var els = document.getElementsByTagName("div");
var docEl = document.documentElement;
for (var i = 0; i < els.length; i++) {
var rect = els[i].getBoundingClientRect();
var rectTop = rect.top + window.pageYOffset - docEl.clientTop;
var rectLeft = rect.left + window.pageXOffset - docEl.clientLeft;
els[i].innerHTML = "<b>" + rectLeft + ", " + rectTop + "</b>";
}
div {
width: 100px;
height: 100px;
background-color: red;
border: 1px solid black;
}
#rel {
position: relative;
left: 10px;
top: 10px;
}
#abs {
position: absolute;
top: 250px;
left: 250px;
}
<div id="rel"></div>
<div id="abs"></div>
<div></div>
To get the total offset of an element, you could recursively sum up all parent offsets:
function getParentOffset(el): number {
if (el.offsetParent) {
return el.offsetParent.offsetTop + getParentOffset(el.offsetParent);
} else {
return 0;
}
}
with this utility function the total top offset of a dom element is:
el.offsetTop + getParentOffset(el);
This is the best code I've managed to create (works in iframes as well, unlike jQuery's offset()). Seems webkit has a bit of a different behavior.
Based on meouw's comment:
function getOffset( el ) {
var _x = 0;
var _y = 0;
while( el && !isNaN( el.offsetLeft ) && !isNaN( el.offsetTop ) ) {
_x += el.offsetLeft - el.scrollLeft;
_y += el.offsetTop - el.scrollTop;
// chrome/safari
if ($.browser.webkit) {
el = el.parentNode;
} else {
// firefox/IE
el = el.offsetParent;
}
}
return { top: _y, left: _x };
}
While this is very likely to be lost at the bottom of so many answers, the top solutions here were not working for me.
As far as I could tell neither would any of the other answers have helped.
Situation:
In an HTML5 page I had a menu that was a nav element inside a header (not THE header but a header in another element).
I wanted the navigation to stick to the top once a user scrolled to it, but previous to this the header was absolute positioned (so I could have it overlay something else slightly).
The solutions above never triggered a change because .offsetTop was not going to change as this was an absolute positioned element. Additionally the .scrollTop property was simply the top of the top most element... that is to say 0 and always would be 0.
Any tests I performed utilizing these two (and same with getBoundingClientRect results) would not tell me if the top of the navigation bar ever scrolled to the top of the viewable page (again, as reported in console, they simply stayed the same numbers while scrolling occurred).
Solution
The solution for me was utilizing
window.visualViewport.pageTop
The value of the pageTop property reflects the viewable section of the screen, therefore allowing me to track where an element is in reference to the boundaries of the viewable area.
Probably unnecessary to say, anytime I am dealing with scrolling I expect to use this solution to programatically respond to movement of elements being scrolled.
Hope it helps someone else.
IMPORTANT NOTE: This appears to work in Chrome and Opera currently & definitely not in Firefox (6-2018)... until Firefox supports visualViewport I recommend NOT using this method, (and I hope they do soon... it makes a lot more sense than the rest).
UPDATE:
Just a note regarding this solution. While I still find what I discovered to be very valuable for situations in which "...programmatically respond to movement of elements being scrolled." is applicable. The better solution for the problem that I had was to use CSS to set position: sticky on the element. Using sticky you can have an element stay at the top without using javascript (NOTE: there are times this will not work as effectively as changing the element to fixed but for most uses the sticky approach will likely be superior)
UPDATE01:
So I realized that for a different page I had a requirement where I needed to detect the position of an element in a mildly complex scrolling setup (parallax plus elements that scroll past as part of a message).
I realized in that scenario that the following provided the value I utilized to determine when to do something:
let bodyElement = document.getElementsByTagName('body')[0];
let elementToTrack = bodyElement.querySelector('.trackme');
trackedObjPos = elementToTrack.getBoundingClientRect().top;
if(trackedObjPos > 264)
{
bodyElement.style.cssText = '';
}
Hope this answer is more widely useful now.
I did it like this so it was cross-compatible with old browsers.
// For really old browser's or incompatible ones
function getOffsetSum(elem) {
var top = 0,
left = 0,
bottom = 0,
right = 0
var width = elem.offsetWidth;
var height = elem.offsetHeight;
while (elem) {
top += elem.offsetTop;
left += elem.offsetLeft;
elem = elem.offsetParent;
}
right = left + width;
bottom = top + height;
return {
top: top,
left: left,
bottom: bottom,
right: right,
}
}
function getOffsetRect(elem) {
var box = elem.getBoundingClientRect();
var body = document.body;
var docElem = document.documentElement;
var scrollTop = window.pageYOffset || docElem.scrollTop || body.scrollTop;
var scrollLeft = window.pageXOffset || docElem.scrollLeft || body.scrollLeft;
var clientTop = docElem.clientTop;
var clientLeft = docElem.clientLeft;
var top = box.top + scrollTop - clientTop;
var left = box.left + scrollLeft - clientLeft;
var bottom = top + (box.bottom - box.top);
var right = left + (box.right - box.left);
return {
top: Math.round(top),
left: Math.round(left),
bottom: Math.round(bottom),
right: Math.round(right),
}
}
function getOffset(elem) {
if (elem) {
if (elem.getBoundingClientRect) {
return getOffsetRect(elem);
} else { // old browser
return getOffsetSum(elem);
}
} else
return null;
}
More about coordinates in JavaScript here: http://javascript.info/tutorial/coordinates
HTML program to show (x, y) of an
element by dragging mouse over it you just copied it and use it on your own
<!DOCTYPE html>
<html>
<head>
<title>
position of an element
</title>
<!-- scropt to get position -->
<script type = "text/javascript">
function getPositionXY(element) {
var rect = element.getBoundingClientRect();
document.getElementById('text').innerHTML
= 'X: ' + rect.x + '<br>' + 'Y: ' + rect.y;
}
</script>
</head>
<body>
<p>Move the mouse over the text</p>
<div onmouseover = "getPositionXY(this)">
Position:
<p id = 'text'></p>
</div>
</body>
</html>
i could just like element.offsetLeft or element.offsetTop. Example :
document.getElementById('profileImg').offsetLeft
I successfully used Andy E's solution to position a bootstrap 2 modal depending on what link in a table row a user clicks on. The page is a Tapestry 5 page and javascript below is imported in the java page class.
javascript:
function setLinkPosition(clientId){
var bodyRect = document.body.getBoundingClientRect(),
elemRect = clientId.getBoundingClientRect(),
offset = elemRect.top - bodyRect.top;
offset = offset + 20;
$('#serviceLineModal').css("top", offset);
}
My modal code:
<div id="serviceLineModal" class="modal hide fade add-absolute-position" data-backdrop="static"
tabindex="-1" role="dialog" aria-labelledby="myModalLabel" aria-hidden="true" style="top:50%;">
<div class="modal-header">
<button type="button" class="close" data-dismiss="modal" aria-hidden="true">x</button>
<h3 id="myModalLabel">Modal header</h3>
</div>
<div class="modal-body">
<t:zone t:id="modalZone" id="modalZone">
<p>You selected service line number: ${serviceLineNumberSelected}</p>
</t:zone>
</div>
<div class="modal-footer">
<button class="btn" data-dismiss="modal" aria-hidden="true">Close</button>
<!-- <button class="btn btn-primary">Save changes</button> -->
</div>
The link in the loop:
<t:loop source="servicesToDisplay" value="service" encoder="encoder">
<tr style="border-right: 1px solid black;">
<td style="white-space:nowrap;" class="add-padding-left-and-right no-border">
<a t:type="eventLink" t:event="serviceLineNumberSelected" t:context="service.serviceLineNumber"
t:zone="pageZone" t:clientId="modalLink${service.serviceLineNumber}"
onmouseover="setLinkPosition(this);">
<i class="icon-chevron-down"></i> <!-- ${service.serviceLineNumber} -->
</a>
</td>
And the java code in the page class:
void onServiceLineNumberSelected(String number){
checkForNullSession();
serviceLineNumberSelected = number;
addOpenServiceLineDialogCommand();
ajaxResponseRenderer.addRender(modalZone);
}
protected void addOpenServiceLineDialogCommand() {
ajaxResponseRenderer.addCallback(new JavaScriptCallback() {
#Override
public void run(JavaScriptSupport javascriptSupport) {
javascriptSupport.addScript("$('#serviceLineModal').modal('show');");
}
});
}
Hope this helps someone, this post helped out.
After much research and testing this seems to work
function getPosition(e) {
var isNotFirefox = (navigator.userAgent.toLowerCase().indexOf('firefox') == -1);
var x = 0, y = 0;
while (e) {
x += e.offsetLeft - e.scrollLeft + (isNotFirefox ? e.clientLeft : 0);
y += e.offsetTop - e.scrollTop + (isNotFirefox ? e.clientTop : 0);
e = e.offsetParent;
}
return { x: x + window.scrollX, y: y + window.scrollY };
}
see http://jsbin.com/xuvovalifo/edit?html,js,output
Just thought I'd throw this out there as well.
I haven't been able to test it in older browsers, but it works in the latest of the top 3. :)
Element.prototype.getOffsetTop = function() {
return ( this.parentElement )? this.offsetTop + this.parentElement.getOffsetTop(): this.offsetTop;
};
Element.prototype.getOffsetLeft = function() {
return ( this.parentElement )? this.offsetLeft + this.parentElement.getOffsetLeft(): this.offsetLeft;
};
Element.prototype.getOffset = function() {
return {'left':this.getOffsetLeft(),'top':this.getOffsetTop()};
};
This is easy as two lines in JS :
var elem = document.getElementById("id");
alert(elem.getBoundingClientRect());
Since different browsers are rendering border, padding, margin and etc in different way. I wrote a little function to retrieve top and left positions of specific element in every root element that you want in precise dimension:
function getTop(root, offset) {
var rootRect = root.getBoundingClientRect();
var offsetRect = offset.getBoundingClientRect();
return offsetRect.top - rootRect.top;
}
For retrieve left position you must return:
return offsetRect.left - rootRect.left;
Get position of div in respect to left and Top
var elm = $('#div_id'); //get the div
var posY_top = elm.offset().top; //get the position from top
var posX_left = elm.offset().left; //get the position from left
NOTE: Exact description of question follows CSS below. Sample code can be seen in this fiddle.
I have a parent div with a list of child divs within it, that looks like the following:
HTML for said container and children is:
<div class="categories_container">
<div class="category one">One</div>
<div class="category two">Two</div>
<div class="category three">Three</div>
<div class="category four">Four</div>
<div class="category five">Five</div>
<div class="category six">Six</div>
</div>
Where the classes .one, .two, .three, etc... are their relative position in the list.
The children elements are positioned with absolute positioning, within their parent.
CSS as follows (some properties not shown for simplicity):
.categories_container {
height: 324px;
width: 100%;
position: relative;
}
.category {
height: 50px;
width: 98%;
position: absolute;
left: 0px;
z-index: 0;
}
.one {
top: 0px;
}
.two {
top: 54px;
}
.three {
top: 108px;
}
.four {
top: 162px;
}
.five {
top: 216px;
}
.six {
top: 270px;
}
As can be seen in this fiddle, you can click (and hold) on any one of the child elements and move it up and down within the parent div. When you release the mouse, the selected child snaps back to its original position.
Question:
How can I detect if the selected element has been dragged overtop of another? I don't only want to know if they are overlapping, but would like to put a range on it. Something like...
if(center of current child is overtop a set range within another child){
do stuff...
}
What I'd like to do for now (as a proof of concept) is to have the underneath child's background color change WHILE the vertical center of the selected child is within the range 0.4-0.6 of the bottom child's height. If the selected child is dragged out of said region, the background should change back.
I've tried something like:
$('.category').mouseover(function(){
if(dragging){
... execute code...
}
});
But it seems that if I am dragging one element over the other, the bottom element cannot see the mouse, and so the function is never executed.
Also:
I've tried a few different methods to keep the cursor as a pointer while dragging, but no matter what it switches to the text cursor whilst dragging. So any help with that would also be appreciated.
For the pointer thing I've tried putting $(this).css('cursor', 'pointer'); in the mousedown and mouse move functions, but to no avail.
Thanks in advance! Sorry if any of this is confusing.
Here is the solution I came up with, purely with JS and JQuery, with no external libraries required and without using JQueryUI Sortables.
HTML:
<div class="list_container">
<div class="list_item">One</div>
<div class="list_item">Two</div>
<div class="list_item">Three</div>
<div class="list_item">Four</div>
<div class="list_item">Five</div>
<div class="list_item">Six</div>
</div>
where list_container holds the individual list_item elements. Is it the latter of the two which can be moved around to create your sorted list. You can put just about anything you'd like within list_item and it'll still work just fine.
CSS:
.list_container {
position: relative;
}
.list_item {
position: absolute;
z-index: 0;
left: 0px;
}
.list_item.selected {
z-index: 1000;
}
Please visit this fiddle for the full list of CSS rules (only necessary ones are shown above).
JavaScript:
I'll go through this bit-by-bit and then show the full code at the bottom.
First off, I defined an array that matches up index numbers with their written counterparts
var classes = new Array("one", "two", "three", ...);
This is used to create classes dynamically (upon page load). These classes are used to order the list. You are only required to populate this array with as many items as you will have in your list. This is the one downfall of the code I have written and am unsure of how to overcome this issue (would be VERY tedious to enter in the elements for a list of hundreds of items, or more!)
Next, a few other variables:
var margin = 2; // Space desired between each list item
var $el; // Used to hold the ID of the element that has been selected
var oldPos = 0; // The position of the selected element BEFORE animation
var newPos = 0; // The position of the selected element AFTER animation (also current position)
var dragging = false; // Whether or not an item is being moved
var numElements = $('.list_container > div').length;
// selectionHeight is the height of each list element (assuming all the same height)
// It includes the div height, the height of top and bottom borders, and the desired margin
var selectionHeight = $('.list_container .list_item').height() + parseInt($('.list_container .list_item').css("border-bottom-width")) + parseInt($('.list_container .list_item').css("border-top-width")) + margin;
var classInfo = ''; // classInfo will be populated with the information that is used to dynamically create classes upon page load
When page loads, go through each list_item and assign it a class according to its initial position in the list. Also add to classInfo the location of the TOP of the list item.
$('.list_container .list_item').each(function (index) {
$(this).addClass(classes[index]);
classInfo += '.' + classes[index] + ' {top: ' + index * selectionHeight + 'px;}\n';
});
Now, using classInfo that was created above, dynamically write the classes to the page.
var style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = classInfo;
document.getElementsByTagName('head')[0].appendChild(style);
The above bit of code will write the required classes into the HTML of the page. If you view the source of the page, you can see the classes in the head of the page.
Now for the ordering part. First, mousedown
$('.list_item').mousedown(function (ev) {
$el = $(this);
oldPos = $el.index() + 1;
newPos = oldPos;
dragging = true;
startY = ev.clientY; // Gets the current mouse position
startT = parseInt($el.css('top')); // Gets the current position of the TOP of the item
$el.addClass('selected'); // Adding class brings it to top (z-index) and changes color of list item
});
Next, the mousemove and mouseup functions are tied together
$(window).mousemove(function (ev) { // Use $(window) so mouse can leave parent div and still work
if (dragging) {
$el.attr('class', 'list_item') // Remove the numbered class (.one, .two, etc)
$el.addClass('selected'); // Add this class back for aesthetics
// ----- calculate new top
var newTop = startT + (ev.clientY - startY);
$el.css('cursor', 'pointer');
// ------
//------ stay in parent
var maxTop = $el.parent().height() - $el.height();
newTop = newTop < 0 ? 0 : newTop > maxTop ? maxTop : newTop;
$el.css('top', newTop);
//------
newPos = getPos(newTop, selectionHeight); // Determine what the current position of the selected list item is
// If the position of the list item has changed, move the position's current element out of the way and reassign oldPos to newPos
if (oldPos != newPos) {
moveThings(oldPos, newPos, selectionHeight);
oldPos = newPos;
}
}
}).mouseup(function () {
dragging = false; // User is no longer dragging
$el.removeClass('selected'); // Element is no longer selected
setNewClass($el, newPos); // Set the new class of the moved list item
$el.css('top', (newPos - 1) * selectionHeight); // Position the moved element where it belongs. Otherwise it'll come to rest where you release it, not in its correct position.
});
Finally, the three functions getPos, moveThings and setNewClass are as follows:
function getPos(a, b) { // a == newTop, b == selectionHeight
return Math.round( (a/b) + 1 );
}
getPos works by finding out which region the selected element is currently in. If newTop is less than .5b, then it is in region 1. If between .5b and 1.5b, then it is region 2. If between 1.5b and 2.5b, then in region 3. And so on. Write out a few cases on a piece of paper and it'll make sense what is happening.
function moveThings(a, b, c) { // a == oldPos, b == newPos, c == selectedHeight
var first = classes[b - 1]; // What is the current class of the item that will be moved
var $newEl = $('.list_container .' + first); // ID of element that will be moved
if (a < b) { // oldPos less than newPos
var second = classes[b - 2]; // The new class of the moved element will be one less
var newTop = parseInt($newEl.css('top')) - c; // Top of element will move up
} else { // oldPos more than newPos
var second = classes[b]; // The new class of the moved element will be one more
var newTop = parseInt($newEl.css('top')) + c; // Top of element will move down
}
// The following line of code is required, otherwise the following animation
// will animate of from top=0px to the new position (opposed to from top=currentPosition)
// Try taking it out and seeing
$newEl.css('top', parseInt($newEl.css('top')));
$newEl.removeClass(first); // Remove the current numbered class of element to move
// Move element and remove the added style tags (or future animations will get buggy)
$newEl.animate({top: newTop}, 300, function () {
$newEl.removeAttr('style');
});
$newEl.addClass(second); // Add the new numbered class
return false; // Cleans up animations
}
The function above is what does the actual animation part and moves the list items around to accommodate the selected list item.
function setNewClass(e, a) { // e == selected element, a == newPos
// Remove 'selected' class, then add back the 'list_item' class and the new numbered class
e.attr('class', 'list_item').addClass(classes[a-1]);
}
** All JavaScript together: **
var classes = new Array("one", "two", "three", "four", "five", "six", "seven", "eight", "nine", "ten", "eleven", "twelve", "thirteen", "fourteen", "fifteen", "sixteen", "seventeem", "eighteen", "nineteen", "twenty", "twentyone", "twentytwo", "twentythree", "twentyfour");
$(document).ready(function () {
var margin = 2;
var $el;
var oldPos = 0;
var newPos = 0;
var dragging = false;
var selectionHeight = $('.list_container .list_item').height() + parseInt($('.list_container .list_item').css("border-bottom-width")) + parseInt($('.list_container .list_item').css("border-top-width")) + margin;
var classInfo = '';
$('.list_container .list_item').each(function (index) {
$(this).addClass(classes[index]);
classInfo += '.' + classes[index] + ' {top: ' + index * selectionHeight + 'px;}\n';
});
var style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = classInfo;
document.getElementsByTagName('head')[0].appendChild(style);
$('.list_item').mousedown(function (ev) {
$el = $(this);
oldPos = $el.index() + 1;
newPos = oldPos;
dragging = true;
startY = ev.clientY;
startT = parseInt($el.css('top'));
$el.addClass('selected');
});
$(window).mousemove(function (ev) {
if (dragging) {
$el.attr('class', 'list_item')
$el.addClass('selected');
// ----- calculate new top
var newTop = startT + (ev.clientY - startY);
$el.css('cursor', 'pointer');
// ------
//------ stay in parent
var maxTop = $el.parent().height() - $el.height();
newTop = newTop < 0 ? 0 : newTop > maxTop ? maxTop : newTop;
$el.css('top', newTop);
//------
newPos = getPos(newTop, selectionHeight);
if (oldPos != newPos) {
moveThings(oldPos, newPos, selectionHeight);
oldPos = newPos;
}
}
}).mouseup(function () {
dragging = false;
$el.removeClass('selected');
setNewClass($el, newPos);
$el.css('top', (newPos - 1) * selectionHeight);
});
});
function getPos(a, b) { // a == topPos, b == selectionHeight
return Math.round((a / b) + 1);
}
function moveThings(a, b, c) { // a == oldPos, b == newPos, c == selectedHeight
var first = classes[b - 1];
var $newEl = $('.list_container .' + first);
if (a < b) { // oldPos less than newPos
var second = classes[b - 2];
var newTop = parseInt($newEl.css('top')) - c;
} else { // oldPos more than newPos
var second = classes[b];
var newTop = parseInt($newEl.css('top')) + c;
}
$newEl.css('top', parseInt($newEl.css('top')));
$newEl.removeClass(first);
$newEl.animate({
top: newTop
}, 300, function () {
$newEl.removeAttr('style');
});
$newEl.addClass(second);
return false; // Cleans up animations
}
function setNewClass(e, a) { // e == selected element, a == newPos
e.attr('class', 'list_item').addClass(classes[a - 1]);
}
I'm making a scheduling calendar. The events are horizontal blocks (Google Cal has vertical ones). And because I have loads of events in one date I want the events to stack onto eachother without wasting any space, like this:
I did find plugins:
http://masonry.desandro.com/
http://isotope.metafizzy.co/
http://packery.metafizzy.co/
But I'm not keen on using a 30kb plugin just to do this simple thing.
To clarify: because this is a timeline, the div-events cannot move left/right, but must fit itself vertically amongst other div-events.
My own solution is a 2.6kb (commented) jQuery script, that uses absolute positioning for events and a div as a container for each row.
This script generates randomly size bars. Each new bar checks for space in each row from top-down. I'm using percentages, because that way calculating bar position against time will be easy (100% / 24h).
http://jsfiddle.net/cj23H/5/
Though works and is efficient enough, it feels bulky. You're welcome to improve.
jQuery code from my jsfiddle:
function rand() {
return Math.floor(Math.random() * 101);
}
function get_target_row(width, left) {
var i = 0;
var target_found = false;
// Loop through all the rows to see if there's space anywhere
while (target_found === false) {
// Define current row selector
var target_i = '.personnel#row' + i;
// Add row if none
if ($(target_i).length === 0) {
$('body').append('<div class="personnel" id="row' + i + '"></div>');
}
// See if there's space
if ($(target_i).children().length === 0) {
target_found = $(target_i);
} else {
var spaceFree = false;
// Check collision for each child
$(target_i).children().each(function () {
// Get left and right coordinates
var thisWidthPx = parseFloat($(this).css('width'), 10);
var thisWidthParentPx = parseFloat($(this).parent().css('width'), 10);
var thisWidth = (thisWidthPx / thisWidthParentPx * 100);
var thisLeftPx = parseFloat($(this).css('left'), 10);
var thisLeftParentPx = parseFloat($(this).parent().css('left'), 10);
var thisLeft = (thisLeftPx / thisWidthParentPx * 100);
var thisRight = thisLeft + thisWidth;
var right = left + width;
// Sexy way for checking collision
if ((right > thisLeft && right < thisRight) || (left < thisRight && left > thisLeft) || (thisLeft > left && thisLeft < right) || (thisRight < right && thisRight > left)) {
spaceFree = false;
return false;
} else {
spaceFree = true;
}
});
// If no children have collided break the loop
if (spaceFree === true) {
target_found = $(target_i);
}
}
i++;
}
// If after all the while loops target is still not found...
if (target_found === false) {
return false;
}
// Else, if target is found, return it.
return target_found;
}
// Generate random bars
for (var i = 0; i < 10; i++) {
var width = rand()/2;
var left = rand()/2;
var right = left + width;
var target = get_target_row(width, left);
target.append('<div class="block" style="width:' + width + '%;position:absolute;left:' + left + '%;background-color:rgba(' + rand() + ',' + rand() + ',' + rand() + ',0.4)" id="bar'+i+'">' + 'b' + i + '</div>');
}
CSS:
.block {
position: absolute;
background-color: rgba(200, 100, 100, 0.4);
height: 32px;
}
.personnel {
position: relative;
float: left;
width: 100%;
height: 33px;
}
I am displaying in my webpage a number of images within a div the div and images are created dynamically with a looping.
I need to get the width and height of the each image by using the jquery without using id like this
document.getElementById('Image/div id');
because there will a lot of images dynamically created by the loop depend upon the conditions
so, is there any way to get the height and width of the image when user hover/click the image
I struck with this for a long and been here finally hopes i get a solution
you can use jQuery on() to attach a handler to the nearest common parent container. that way, you can at least control which subset of images you want this function to take effect.
$('#container').on('mouseover','img',function(){
var width = $(this).width();
var height = $(this).height();
});
like:
<div>
<img> //will not affect this one since it's not under "#container"
</div>
<div id="container">
<img> //the handler affects this one
<div>
<img> //the handler also affects this one
</div>
</div>
I'd suggest, if you want to show this information on the page:
$('img').hover(
function(){
var h = $(this).height(),
w = $(this).width();
$('<div />').insertAfter($(this)).text('height: ' + h + '; width: ' + w +'.');
},
function(){
$(this).next('div').remove();
});
JS Fiddle demo.
Almost pointless edit to make it a little bit prettier by reducing the calls to $(this) and coupling it to some CSS:
$('img').hover(
function(){
var that = $(this),
h = that.height(),
w = that.width();
$('<div />')
.css('width',w)
.text('height: ' + h + '; width: ' + w +'.')
.insertAfter(that);
},
function(){
$(this).next('div').remove();
});
CSS:
div {
display: block;
position: relative;
}
div > div {
position: absolute;
top: 0;
left: 0;
color: #f90;
background-color: #000;
background-color: rgba(0,0,0,0.6);
}
JS Fiddle demo.
Edited because jQuery's not really necessary for this effect (albeit it does simplify the implementation), so: a plain JavaScript alternative:
var img = document.getElementsByTagName('img');
for (var i=0,len=img.length;i<len;i++){
img[i].onmouseover = function(){
var that = this,
h = that.offsetHeight,
w = that.offsetWidth,
p = that.parentNode,
d = document.createElement('div');
d.style.width = w + 'px';
d.textContent = 'Width: ' + w + '; height: ' + h + '.';
p.appendChild(d);
};
img[i].onmouseout = function(){
var that = this;
that.parentNode.removeChild(that.nextSibling);
};
}
JS Fiddle demo.
Final edit (I think), because I couldn't remember the compatibility for node.textContent, I thought this amendment might aid compatibility with lower versions of IE (using document.createTextNode() instead of relying on node.textContent/node.innerText and so on...):
var img = document.getElementsByTagName('img');
for (var i=0,len=img.length;i<len;i++){
img[i].onmouseover = function(){
var that = this,
h = that.offsetHeight,
w = that.offsetWidth,
p = that.parentNode,
d = document.createElement('div'),
text = document.createTextNode('Width: ' + w + '; height: ' + h + '.');
d.appendChild(text);
d.style.width = w + 'px';
p.appendChild(d);
};
img[i].onmouseout = function(){
var that = this;
that.parentNode.removeChild(that.nextSibling);
};
}
JS Fiddle demo.
While I don't have IE 7, or lower, the above does work in IE 8 at least. If anyone has comments about functionality in IE 6 or 7 I'd be interested..!
References:
'Plain' JavaScript:
document.createElement.
document.createTextNode().
element.offsetHeight.
element.offsetWidth.
element.style.
node.appendChild.
node.parentNode.
node.removeChild.
node.textContent.
jQuery:
height().
hover().
insertAfter().
next().
remove().
text().
width().
Does this solve your issue?
$('img').hover(function() {
console.log($(this).width());
console.log($(this).height());
});
Use $(this) to refer to the image being hovered.
$("#div_id").hover(function(){
alert("H:" + $(this).height() + " W:" + $(this).width() );
});
$(".img").mouseover(function() {
var $div = $(this);
var $item = $div.find("img");
var width = $item.width();
var height = $item.height();
}
try this.
I'm trying to do what the title says. I've seen that font-size can be a percentage. So my guess was that font-size: 100%; would do it, but no.
Here is an example: http://jsfiddle.net/xVB3t/
Can I get some help please?
(If is necesary to do it programatically with js there is no problem)
This question might help you out but I warn you though this solves it through jQuery:
Auto-size dynamic text to fill fixed size container
Good luck.
The OP of that question made a plugin, here is the link to it (& download)
BTW I'm suggesting jQuery because as Gaby pointed out this can't be done though CSS only and you said you were willing to use js...
Can't be done with CSS.
100% is in relation to the computed font-size of the parent element.
reference: http://www.w3.org/TR/CSS2/fonts.html#font-size-props
For a jQuery solution look at Auto-size dynamic text to fill fixed size container
I was looking into this for work and I liked tnt-rox's answer, but I couldn't help but notice that it had some extra overhead that could be cut out.
document.body.setScaledFont = function(){
this.style.fontSize = (this.offsetWidth*0.35)+'%';
return this;
}
document.body.setScaledFont();
Cutting out the overhead makes it run a little bit quicker if you add it to an onresize event.
If you are only looking to have the font inside a specific element set to resize to fit, you could also do something like the following
window.onload = function(){
var scaledFont = function(el){
if(el.style !== undefined){
el.style.fontSize = (el.offsetWidth*0.35)+'%';
}
return el;
}
navs = document.querySelectorAll('.container>nav'),
i;
window.onresize = function(){
for(i in navs){
scaledFont(navs[i]);
}
};
window.onresize();
};
I just noticed nicolaas' answer also had some extra overhead. I've cleaned it up a bit. From a performance perspective, I'm not really a fan of using a while loop and slowly moving down the size until you find one that fits.
function setPageHeaderFontSize(selector) {
var $ = jQuery;
$(selector).each(function(i, el) {
var text = $(el).text();
if(text.length) {
var span = $("<span>").css({
visibility: 'hidden',
width: '100%',
position: 'absolute',
'line-height': '300px',
top: 0,
left: 0,
overflow: 'visible',
display: 'table-cell'
}).text(text),
height = 301,
fontSize = 200;
$(el).append(span);
while(height > 300 && fontSize > 10) {
height = span.css("font-size", fontSize).height();
fontSize--;
}
span.remove();
$(el).css("font-size", fontSize+"px");
}
});
}
setPageHeaderFontSize("#MyDiv");
And here is an example of my earlier code using jquery.
$(function(){
var scaledFont = function(el){
if(el.style !== undefined){
el.style.fontSize = (el.offsetWidth*0.35)+'%';
}
return el;
};
$(window).resize(function(){
$('.container>nav').each(scaledFont);
}).resize();
});
A bit late but this is how I approach this problem:
document.body.setScaledFont = function() {
var f = 0.35, s = this.offsetWidth, fs = s * f;
this.style.fontSize = fs + '%';
return this
}
document.body.setScaledFont();
The base document font is now set.
For the rest of your elements in the dom set font sizes as % or em and they will scale proportionately.
here I have a mootools solution:
Element.implement("fitText", function() {
var e = this.getParent();
var maxWidth = e.getSize().x;
var maxHeight = e.getSize().y;
console.log(maxWidth);
var sizeX = this.getSize().x;
var sizeY = this.getSize().y;
if (sizeY <= maxHeight && sizeX <= maxWidth)
return;
var fontSize = this.getStyle("font-size").toInt();
while( (sizeX > maxWidth || sizeY > maxHeight) && fontSize > 4 ) {
fontSize -= .5;
this.setStyle("font-size", fontSize + "px");
sizeX = this.getSize().x;
sizeY = this.getSize().y;
}
return this;
});
$$("span").fitText();
Here is another jQuery solution ...
/**
* Resizes page header font-size for the text to fit.
* basically we add a hidden span into the header,
* put the text into it and then keep reducing the super large font-size
* for as long as the height of the span exceeds the super
* tall line-height set for the test (indicating there is more than one line needed
* to show the text).
*/
function setPageHeaderFontSize(selectorString) {
jQuery(selectorString).each(
function(i, el) {
var text = jQuery(el).text();
var length = text.length;
if(length) {
var id = "TestToSeeLengthOfElement_" + i;
jQuery(el).append("<span style='visibility: hidden; width: 100%; position: absolute; line-height: 300px; top: 0; left: 0; overflow: visible; display: table-cell;' id='"+id+"'>"+text+"</span>");
var innerEl = jQuery("#"+id);
var height = 301;
var fontSize = 200;
while(height > 300 && fontSize > 10) {
height = jQuery(innerEl).css("font-size", fontSize).height();
fontSize--;
}
jQuery(innerEl).remove();
jQuery(el).css("font-size", fontSize+"px");
}
}
);
}
//you can run it like this... using any jQuery enabled selector string (e.g. h1.pageHeaders works fine).
setPageHeaderFontSize("#MyDiv");
Here's a way to find the height of the text that you are using.
It's simple and only uses javascript. You can use this to adjust your text relative to the height you want.
function getTextHeight(text, fontSize) {
var numberOfLines = 0;
var STL = text;
for(var i = 0; i < STL.length; i++){
if(STL[i] === '<'){
try{
if(STL[i + 1] === 'b' && STL[i + 2] === 'r' && STL[i + 3] === '>'){
numberOfLines++;
}
}
catch(err){
break;
}
}
return (numberOfLines + 1) * fontSize;
}