onhover how to get the image width and height using jquery - javascript

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.

Related

javascript function to vertically center element

I'm trying to write a function to vertically center elements if they have a class called "vcenter(#)". For example, vcenter1 vcenter2. It's supposed to take the element's parent's innerheight and subtract the element's innerheight then divide by 2. The value then is applied to the css as the margin-top. It doesn't work though. Please help!
$(document).ready(function(){
for (i=1; i<3; i++){
var childID = $(".vcenter" + i);
var parent = childID.parent().innerHeight();
var child = childID.innerHeight();
var marginTop = (parent - child)/2 + 'px';
$(childID).css({"margin-top", marginTop})
}
});
How about this...
http://jsfiddle.net/mVn9S/
$(document).ready(function () {
$('.vcenter').each(function () {
var parent = $(this).parent().innerHeight();
var child = $(this).innerHeight();
$(this).css({
'margin-top': ((parent - child) / 2) + 'px'
});
});
});
Have you considered using CSS3 Flexbox with a polyfill for old versions of IE? Might be less work.
Change your code to look like this:
$(document).ready(function(){
for (i=1; i<3; i++){
var childElement = $(".vcenter" + i);
var parent = childElement.parent().innerHeight();
var child = childElement.innerHeight();
var marginTop = (parent - child) / 2;
childElement.css({"margin-top": marginTop});
}
});
Notice use of ; at the end of lines - it's a good habit even in JS.
I don't know how your HTML looks but probably this could be easily generalized for all elements with .vcenter class:
$(document).ready(function(){
$('.vcenter').each(function() {
var childElement = $(this);
var parent = childElement.parent().innerHeight();
var child = childElement.innerHeight();
var marginTop = (parent - child) / 2;
childElement.css({"margin-top": marginTop});
});
});

Change div's width by a value in JS

How to change div's width by a certain value, like this:
someDiv.style.width += "100px";
It works when I want to set a value (i.e. width = "100px") but the problem is with += operator.
This would work for a vanilla javascript solution (since you didn't mention jquery):
var someDiv = document.getElementById("someDiv");
var w = 0;
if (typeof someDiv.clip !== "undefined") {
w = someDiv.clip.width;
} else {
if (someDiv.style.pixelWidth) {
w = someDiv.style.pixelWidth;
} else {
w = someDiv.offsetWidth;
}
}
someDiv.style.width = (w + 100) + "px";
<div id="test" style="height:100px"></div>
var elem=document.getElementById("test");
height=parseInt(elem.style.height);
height+=100;
height+="px"
console.log(height);
Try the following
http://jsfiddle.net/CME3Y/
That is because Javascript can't understand what "100px" + "100px" means, since those are string values.
I would do it like this using jQuery:
$(someDiv).width($(someDiv).width() + 100);
var currentwidth= $('#div').width();
$('#div').width(currentwidth +100);
http://jsfiddle.net/dolours/CME3Y/1/
Also you can use this https://stackoverflow.com/a/6179629/1479798

Displaying images like Google Image Search

Does anybody know of a script that will let me diplay image results in the way that Google Image Search does (image grid view) with hover to enlarge and details? Something that I can just "plug-and-play" so to speak.
Have a look at Masonry http://masonry.desandro.com/
First, you need to put all images inside a container element:
<div class="parent">
<img src="">
<img src="">
<img src="">
</div>
Then you need to make sure that the images are displayed in one line. This can be done by e.g. float: left. You should also set vertical-align to remove the small gap underneath each image:
img {
float: left;
vertical-align: top;
}
Finally you need some JavaScript to loop through all images and calculate the ideal rowHeight based on their dimensions. The only thing you need to tell this algorithm is the maximum row height that you want (rowMaxHeight)
// Since we need to get the image width and height, this code should run after the images are loaded
var elContainer = document.querySelector('.parent');
var elItems = document.querySelector('.parent img');
var rowMaxHeight = 250; // maximum row height
var rowMaxWidth = elContainer.clientWidth;
var rowWidth = 0;
var rowRatio = 0;
var rowHeight = 0;
var rowFirstItem = 0;
var rowIsLast = false;
var itemWidth = 0;
var itemHeight = 0;
// Make grid
for (var i = 0; i < elItems.length; i++) {
itemWidth = elItems[i].clientWidth;
itemHeight = elItems[i].clientHeight;
rowWidth += itemWidth;
rowIsLast = i === elItems.length - 1;
// Check if current item is last item in row
if (rowWidth + rowGutterWidth >= gridWidth || rowIsLast) {
rowRatio = Math.min(rowMaxWidth / rowWidth, 1);
rowHeight = Math.floor(rowRatio * rowMaxHeight);
// Now that we know the perfect row height, we just
// have to loop through all items in the row and set
// width and height
for (var x = rowFirstItem; x <= i; x++) {
elItems[i].style.width = Math.floor(rowRatio * itemWidth * (rowMaxHeight/itemHeight)) + 'px';
elItems[i].style.height = rowHeight + 'px';
}
// Reset row variables for next row
rowWidth = 0;
rowFirstItem = i + 1;
}
}
Note that this code is not tested and a very simplified version of what this vanilla JavaScript plugin does: https://fld-grd.js.org
Two solutions that I have found so far.
tutorial blog
jsfiddle
$(function() {
$(window).on('resize', function() {
$('.openEntry').remove();
$('.entry').hide();
var startPosX = $('.preview:first').position().left;
console.log(startPosX);
$('.entry, .preview').removeClass("first last");
$('.entry').each(function() {
if ($(this).prev('.preview').position().left == startPosX) {
$(this).prev('.preview').addClass("first");
$(this).prevAll('.entry:first').addClass("last");
}
});
$('.entry:last').addClass("last");
});
$(window).trigger('resize');
$('.trigger').click(function() {
$('.openEntry').slideUp(800);
var preview = $(this).closest('.preview');
preview.next('.entry').clone().addClass('openEntry').insertAfter(preview.nextAll('.last:first')).slideDown(800);
});
$('body').on('click', '.close', function() {
$('.openEntry').slideUp(800).remove();
});
})
codrops actually puts the photo enlargement/details inline instead of as a modal overlay:
http://tympanus.net/codrops/2013/03/19/thumbnail-grid-with-expanding-preview/
This might be what you are looking for... http://www.gethifi.com/demos/jphotogrid
Have a look at the gPop plugin
DEMO
Download in Github
Check out this jQuery Plugin: https://github.com/brunjo/rowGrid.js
It places images like on the Google image search.
Simply just repeat your images like this:
<img style="float: left; height: 12em; margin-right: 1%; margin-bottom: 0.5em;border:1px solid lightgray" src="ImgSrc " />

Font size auto adjust to fit

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;
}

Javascript: Let user select an HTML element like Firebug?

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);
}

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