Drag and drop functionality for multiple divs (JavaScript) - javascript

I'm working on a small thing where I want the user to be able to create any number of small window objects and then move them around independently on the screen like you would with normal windows. Later I will try to make it so that you can only grab the uppermost part of the windows.
The window objects will all be of the same type, WindowObject, or at least that's been the idea up until now.
The first thing I tried was putting the functionality inside of the objects themselves.
Html
<div id="container">
<div style="width:100px; height:100px; background-color:red">example</div>
<div style="width:100px; height:100px;background-color:red">example</div>
</div>
JavaScript
var WindowObject = function() {
this.xPos = 0;
this.yPos = 0;
};
WindowObject.prototype.addListeners = function() {
this.test1 = this.mouseDown.bind(this);
this.test2 = this.mouseUp.bind(this);
this.container = document.querySelector("#container");
this.container.addEventListener("mousedown", this.test1, false);
window.addEventListener("mouseup", this.test2, false);
};
WindowObject.prototype.move = function(event) {
event.target.style.position = "absolute";
event.target.style.top = (event.clientY - this.yPos) + "px";
event.target.style.left = (event.clientX - this.xPos) + "px";
};
WindowObject.prototype.mouseUp = function() {
window.removeEventListener("mousemove", this.test3, true);
};
WindowObject.prototype.mouseDown = function(event) {
this.xPos = event.clientX - event.target.offsetLeft;
this.yPos = event.clientY - event.target.offsetTop;
this.test3 = this.move.bind(this);
window.addEventListener("mousemove", this.test3, true);
};
This kind of works if you drag the divs very slowly (so that the mouse never leaves them) and also make sure not to overlap other elements. Otherwise the position of the div gets messed up and if there are more than one you may find yourself dragging several divs at the same time.
I also tried putting the functionality in a different kind of object, with some smaller adjustments, but the result was the same.
If you think I should try a different approach all together, please let me know. If not, what am I doing wrong?

Related

Canvas with mousemove blocking links in div underneath

I'm having problems with using the canvas/mousemove. I want to be able to draw on the entire page whenever the mouse moves with a mousemove draw/paint tool but also still click text links that appear in various other divs. The issue I have is that the canvas which is currently fixed, has a transparent background color and is set to 100% width and height blocks the div underneath with a lower z-index, meaning the links can't be clicked. Using pointer-events:none on the canvas isn't the solution as it disables the mousemove effect. If I make the canvas z-index lower than the div's with the links I want to click, the drawing will just appear outside of the div.
What do I need to add or change to make this work? I basically just want to have a functioning webpage with a mouseover effect that will draw over the page whenever it moves.
Below is the script I'm using. And here's an example http://jsfiddle.net/zAF4d/1/
$(function() {
var letsdraw = false;
var theCanvas = document.getElementById('paint');
var ctx = theCanvas.getContext('2d');
theCanvas.width = window.innerWidth;
theCanvas.height = window.innerHeight;
var canvasOffset = $('#paint').offset();
$('#paint').mousemove(function(e) {
if (letsdraw === true) {
ctx.lineTo(e.pageX - canvasOffset.left, e.pageY - canvasOffset.top);
ctx.stroke();
}
});
$('#paint').mousemove(function(e) {
$('.v').css('left', e.clientX + 'px');
$('.h').css('top', e.clientY + 'px');
letsdraw = true;
ctx.strokeStyle = 'blue';
ctx.lineWidth = 0.5;
ctx.lineCap = 'round';
ctx.beginPath();
ctx.moveTo(e.pageX - canvasOffset.left, e.pageY - canvasOffset.top);
});
$(window).mouseout(function(e) {
// bind to the window mouse up, that way if you mouse up and you're not over
// the canvas you'll still get the release of the drawing.
letsdraw = true;
});
});
You say:
The issue I have is that the canvas which is currently fixed, has a transparent background color and is set to 100% width and height blocks the div underneath with a lower z-index, meaning the links can't be clicked. Using pointer-events:none on the canvas isn't the solution as it disables the mousemove effect. If I make the canvas z-index lower than the div's with the links I want to click, the drawing will just appear outside of the div.
I think you need to either do everything on canvas or use DOM and some sort of CSS tricks/animations.
$(function() {
var letsdraw = false;
var theCanvas = document.getElementById('paint');
var ctx = theCanvas.getContext('2d');
.
.
.
//if your div's are not same every time, determine similar prop so u can pull it here on to a canvas...by'ID' || 'Class' ...etc.
var div = document.getElementByID('div01');
dix.x;
div.y;
div.h;
.
.
.
**etc. or if u cannot for any reason pull actual div, just pass on it parameters here....
then u can use them here...*
like making collision model for drawing line over the top of it...
if (mouse.x > div.x && mouse.x < div.x + div.width && mouse.y > div.y && mouse.y < div.height) {
letsdraw = false;
}
....**within draw function
**'onclick' event listener try **
$(div)onclick function();
if whole div was pulled here then it will open links...but even if u pulled just div's parameters u just pass click coordinates on to div if link coordinates match
$(div)onclick function(){
load.page(url: <link>your link</>
}
sorry if mistaken something, didn't run it all together
But give it a go hope it helps;

Unable to change page style via JavaScript

I'm having an issue getting a value from my script make a change on my website. What I'm trying to accomplish, is to allow users to scroll through some elements on my page, going left or right. Keep in mind I'm not very good with JavaScript, so here is what I have so far.
window.onload = makeActive;
function makeActive() {
var showCase = document.getElementById("showcase");
var slides = showCase.getElementsByTagName("div");
var mouseDown = false;
if(window.addEventListener) {
showCase.addEventListener('mousedown',startDrag,false);
document.body.addEventListener('mousemove',drag,false);
document.body.addEventListener('mouseup',stopDrag,false);
}
else if(window.attachEvent) {
showCase.attachEvent('onmousedown',startDrag);
document.body.attachEvent('onmousemove',drag);
document.body.attachEvent('onmouseup',stopDrag);
}
function startDrag(e) {
mouseDown = true;
}
function drag(e) {
if(mouseDown == true) {
for(var i=0; i < slides.length; i += 1) {
slides[i].style.left -= e.clientX + "px";
}
}
}
function stopDrag(e) {
mouseDown = false;
}
}
So basically what this does, is it selects all of the div elements within my showCase element. It proceeds to check whether or not my mouse is hovering over it, and if I am, it will check to see if my mouse is down, if my mouse button is down, it will check for my mouse to move left or right. This all works fine, but the issue comes into play when I try to cycle through my slides, when I try to do any form of an equation to the slides, it gives me a parse error. I think this is because when i try to reference slides[i].style.left comes out as a string. I've tried parsing it to a numeric form, and
stripping it of characters, but that doesn't seem to work. I've also tried using "leftoffset" to grab the value, but no matter what I do, it either gives me an error that is "style.left is undefined", "NaN", or "parse error: declaration dropped". Is there an easier way to do this?
I believe it's this line:
slides[i].style.left -= e.clientX + "px";
If slides[i].style.left has a value like 10px you can't substract an integer value. You need to remove the "px" first:
var leftPos = 0;
if(slides[i].style.left) {
leftPos = slides[i].style.left.toString().replace(/(px)/i, "");
}
slides[i].style.left = (leftPos - e.clientX) + "px";

Dragging elements WITHOUT jQuery

I am currently working on an online presentation software. For the sake of this question imagine it as powerpoint or keynote.
I want to be able to add elements to the slide and then drag them around (live), getting the new position, updating the database.
However I want to do this without any use of external libraries or frameworks, including jQuery.
Can anyone point me in a direction for my research? My current ideas to implement this are pretty messy. Especially the live-dragging is what's giving me headaches.
Thanks!
UPDATE!
the elements look something like this:
<div class="textelement"
data-id="528fc9026803fa9d4b03e506"
data-role="Textelement"
style=" left: 50px;
top: 50px;
z-index: 0;
width: 72px;
height: 72px;">
<div class="textnode">slide: 0 textelement: 0</div>
</div>
While HTML5 does provide native drag and drop, this isn't what you asked for. Check out this simple tutorial to accomplish dragging in vanilla JS: http://luke.breuer.com/tutorial/javascript-drag-and-drop-tutorial.aspx
There is great vanilla JS snippet available, but with one problem - when element start dragged on clickable element, it "clicks" on mouseup: see it on http://codepen.io/ekurtovic/pen/LVpvmX
<div class="draggable">
Dont click me, just drag
</div>
<script>
// external js: draggabilly.pkgd.js
var draggie = new Draggabilly('.draggable');
</script>
here is the "plugin": draggabilly
And, here is my independent solution, working by :class: of the element:
(function (document) {
// Enable ECMAScript 5 strict mode within this function:
'use strict';
// Obtain a node list of all elements that have class="draggable":
var draggable = document.getElementsByClassName('draggable'),
draggableCount = draggable.length, // cache the length
i; // iterator placeholder
// This function initializes the drag of an element where an
// event ("mousedown") has occurred:
function startDrag(evt) {
that.preventDefault();
// The element's position is based on its top left corner,
// but the mouse coordinates are inside of it, so we need
// to calculate the positioning difference:
var diffX = evt.clientX - this.offsetLeft,
diffY = evt.clientY - this.offsetTop,
that = this; // "this" refers to the current element,
// let's keep it in cache for later use.
// moveAlong places the current element (referenced by "that")
// according to the current cursor position:
function moveAlong(evt) {
evt.preventDefault();
var left = parseInt(evt.clientX - diffX);
var top = parseInt(evt.clientY - diffY);
// check for screen boundaries
if (top < 0) { top = 0; }
if (left < 0) { left = 0; }
if (top > window.innerHeight-1)
{ top = window.innerHeight-1; }
if (left > window.innerWidth-1)
{ left = window.innerWidth-1; }
// set new position
that.style.left = left + 'px';
that.style.top = top + 'px';
}
// stopDrag removes event listeners from the element,
// thus stopping the drag:
function stopDrag() {
document.removeEventListener('mousemove', moveAlong);
document.removeEventListener('mouseup', stopDrag);
}
document.addEventListener('mouseup', stopDrag);
document.addEventListener('mousemove', moveAlong);
return false;
}
// Now that all the variables and functions are created,
// we can go on and make the elements draggable by assigning
// a "startDrag" function to a "mousedown" event that occurs
// on those elements:
if (draggableCount > 0) for (i = 0; i < draggableCount; i += 1) {
draggable[i].addEventListener('mousedown', startDrag);
}
}(document));

Synchronized scrolling using jQuery?

I am trying to implement synchronized scrolling for two DIV with the following code.
DEMO
$(document).ready(function() {
$("#div1").scroll(function () {
$("#div2").scrollTop($("#div1").scrollTop());
});
$("#div2").scroll(function () {
$("#div1").scrollTop($("#div2").scrollTop());
});
});
#div1 and #div2 is having the very same content but different sizes, say
#div1 {
height : 800px;
width: 600px;
}
#div1 {
height : 400px;
width: 200px;
}
With this code, I am facing two issues.
1) Scrolling is not well synchronized, since the divs are of different sizes. I know, this is because, I am directly setting the scrollTop value. I need to find the percentage of scrolled content and calculate corresponding scrollTop value for the other div. I am not sure, how to find the actual height and current scroll position.
2) This issue is only found in firefox. In firefox, scrolling is not smooth as in other browsers. I think this because the above code is creating a infinite loop of scroll events.
I am not sure, why this is only happening with firefox. Is there any way to find the source of scroll event, so that I can resolve this issue.
Any help would be greatly appreciated.
You can use element.scrollTop / (element.scrollHeight - element.offsetHeight) to get the percentage (it'll be a value between 0 and 1). So you can multiply the other element's (.scrollHeight - .offsetHeight) by this value for proportional scrolling.
To avoid triggering the listeners in a loop you could temporarily unbind the listener, set the scrollTop and rebind again.
var $divs = $('#div1, #div2');
var sync = function(e){
var $other = $divs.not(this).off('scroll'), other = $other.get(0);
var percentage = this.scrollTop / (this.scrollHeight - this.offsetHeight);
other.scrollTop = percentage * (other.scrollHeight - other.offsetHeight);
// Firefox workaround. Rebinding without delay isn't enough.
setTimeout( function(){ $other.on('scroll', sync ); },10);
}
$divs.on( 'scroll', sync);
http://jsfiddle.net/b75KZ/5/
Runs like clockwork (see DEMO)
$(document).ready(function(){
var master = "div1"; // this is id div
var slave = "div2"; // this is other id div
var master_tmp;
var slave_tmp;
var timer;
var sync = function ()
{
if($(this).attr('id') == slave)
{
master_tmp = master;
slave_tmp = slave;
master = slave;
slave = master_tmp;
}
$("#" + slave).unbind("scroll");
var percentage = this.scrollTop / (this.scrollHeight - this.offsetHeight);
var x = percentage * ($("#" + slave).get(0).scrollHeight - $("#" + slave).get(0).offsetHeight);
$("#" + slave).scrollTop(x);
if(typeof(timer) !== 'undefind')
clearTimeout(timer);
timer = setTimeout(function(){ $("#" + slave).scroll(sync) }, 200)
}
$('#' + master + ', #' + slave).scroll(sync);
});
This is what I'm using. Just call the syncScroll(...) function with the two elements you want to synchronize. I found pawel's solution had issues with continuing to slowly scroll after the mouse or trackpad was actually done with the operation.
See working example here.
// Sync up our elements.
syncScroll($('.scroll-elem-1'), $('.scroll-elem-2'));
/***
* Synchronize Scroll
* Synchronizes the vertical scrolling of two elements.
* The elements can have different content heights.
*
* #param $el1 {Object}
* Native DOM element or jQuery selector.
* First element to sync.
* #param $el2 {Object}
* Native DOM element or jQuery selector.
* Second element to sync.
*/
function syncScroll(el1, el2) {
var $el1 = $(el1);
var $el2 = $(el2);
// Lets us know when a scroll is organic
// or forced from the synced element.
var forcedScroll = false;
// Catch our elements' scroll events and
// syncronize the related element.
$el1.scroll(function() { performScroll($el1, $el2); });
$el2.scroll(function() { performScroll($el2, $el1); });
// Perform the scroll of the synced element
// based on the scrolled element.
function performScroll($scrolled, $toScroll) {
if (forcedScroll) return (forcedScroll = false);
var percent = ($scrolled.scrollTop() /
($scrolled[0].scrollHeight - $scrolled.outerHeight())) * 100;
setScrollTopFromPercent($toScroll, percent);
}
// Scroll to a position in the given
// element based on a percent.
function setScrollTopFromPercent($el, percent) {
var scrollTopPos = (percent / 100) *
($el[0].scrollHeight - $el.outerHeight());
forcedScroll = true;
$el.scrollTop(scrollTopPos);
}
}
If the divs are of equal sizes then this code below is a simple way to scroll them synchronously:
scroll_all_blocks: function(e) {
var scrollLeft = $(e.target)[0].scrollLeft;
var len = $('.scroll_class').length;
for (var i = 0; i < len; i++)
{
$('.scroll_class')[i].scrollLeft = scrollLeft;
}
}
Here im using horizontal scroll, but you can use scrollTop here instead. This function is call on scroll event on the div, so the e will have access to the event object.
Secondly, you can simply have the ratio of corresponding sizes of the divs calculated to apply in this line $('.scroll_class')[i].scrollLeft = scrollLeft;
I solved the sync scrolling loop problem by setting the scroll percentage to fixed-point notation: percent.toFixed(0), with 0 as the parameter. This prevents mismatched fractional scrolling heights between the two synced elements, which are constantly trying to "catch up" with each other. This code will let them catch up after at most a single extra step (i.e., the second element may continue to scroll an extra pixel after the user stops scrolling). Not a perfect solution or the most sophisticated, but certainly the simplest I could find.
var left = document.getElementById('left');
var right = document.getElementById('right');
var el2;
var percentage = function(el) { return (el.scrollTop / (el.scrollHeight - el.offsetHeight)) };
function syncScroll(el1) {
el1.getAttribute('id') === 'left' ? el2 = right : el2 = left;
el2.scrollTo( 0, (percentage(el1) * (el2.scrollHeight - el2.offsetHeight)).toFixed(0) ); // toFixed(0) prevents scrolling feedback loop
}
document.getElementById('left').addEventListener('scroll',function() {
syncScroll(this);
});
document.getElementById('right').addEventListener('scroll',function() {
syncScroll(this);
});
I like pawel's clean solution but it lacks something I need and has a strange scrolling bug where it continues to scroll and my plugin will work on multiple containers not just two.
http://www.xtf.dk/2015/12/jquery-plugin-synchronize-scroll.html
Example & demo: http://trunk.xtf.dk/Project/ScrollSync/
Plugin: http://trunk.xtf.dk/Project/ScrollSync/jquery.scrollSync.js
$('.scrollable').scrollSync();
If you don't want proportional scrolling, but rather to scroll an equal amount of pixels on each field, you could add the value of change to the current value of the field you're binding the scroll-event to.
Let's say that #left is the small field, and #right is the bigger field.
var oldRst = 0;
$('#right').on('scroll', function () {
l = $('#left');
var lst = l.scrollTop();
var rst = $(this).scrollTop();
l.scrollTop(lst+(rst-oldRst)); // <-- like this
oldRst = rst;
});
https://jsfiddle.net/vuvgc0a8/1/
By adding the value of change, and not just setting it equal to #right's scrollTop(), you can scroll up or down in the small field, regardless of its scrollTop() being less than the bigger field. An example of this is a user page on Facebook.
This is what I needed when I came here, so I thought I'd share.
From the pawel solution (first answer).
For the horizzontal synchronized scrolling using jQuery this is the solution:
var $divs = $('#div1, #div2'); //only 2 divs
var sync = function(e){
var $other = $divs.not(this).off('scroll');
var other = $other.get(0);
var percentage = this.scrollLeft / (this.scrollWidth - this.offsetWidth);
other.scrollLeft = percentage * (other.scrollWidth - other.offsetWidth);
setTimeout( function(){ $other.on('scroll', sync ); },10);
}
$divs.on('scroll', sync);
JSFiddle
An other solution for multiple horizontally synchronized divs is this, but it works for divs with same width.
var $divs = $('#div1, #div2, #div3'); //multiple divs
var sync = function (e) {
var me = $(this);
var $other = $divs.not(me).off('scroll');
$divs.not(me).each(function (index) {
$(this).scrollLeft(me.scrollLeft());
});
setTimeout(function () {
$other.on('scroll', sync);
}, 10);
}
$divs.on('scroll', sync);
NB: Only for divs with same width
JSFiddle

without jquery i need to find out if the mouse is over an element, not determine when it becomes over (in case it doesn't move to trigger onmouseover)

without jquery
basically what I am looking for is the ability to see if the mouse is over a div when a countdown finishes
if the user is over the div then perform action for that div
onmouseover only triggers when the mouse crosses the threshold of the div, if the mouse hasn't moved it wouldn't trigger, so that wouldn't work
I need to determine if the mouse is currently over a div at a specific point in time, if it has moved or not from the starting point
all of my hunting has only found onmousover, and nothing to see if the mouse just happens to be there to begin with
I don't have the javascript skills to determine overall coords of div, then map mouse coords and see if it fits there... which is what I believe I need to do
After reading the second answer (the one with millions of a elements) on this SO question, I've came up with this method works without moving the mouse on page load, without involving millions of elements.
HTML
<div id=t></div>
CSS
#t {
/* for illustrative purposes */
width: 10em;
height: 5em;
background-color: #0af;
}
#t:hover {
border-top-style: hidden;
}
JavaScript
document.addEventListener('click', function () {
var c = window.getComputedStyle(document.getElementById('t')).getPropertyValue('border-top-style');
if (c === 'hidden') {
alert('Mouse in box');
} else {
alert('Mouse not in box');
}
}, false);
As stated earlier, bind to the finish event of your countdown instead of the click event on the document.
You may also use any CSS style that's changed on :hover, I chose border-top-style as it is conspicuous. If you're using a border, choose something else.
Here's a jsFiddle.
set a flag to true onmouseover and to false onmouseleave. when countdown finishes if flag is true then it is over element.
HTML
<div id="div-name">the section of the code i am working with has a countdown timer, when it reaches 0 i need to know if the mouse is over a specific box</div>
<button id="notification" onclick="javascript: letsCountIt(5);">click to start countdown</button>
JS
window.ev = false;
document.getElementById('div-name').onmouseover = function () {
window.ev = true;
console.log(window.ev);
}
document.getElementById('div-name').onmouseout = function () {
window.ev = false;
console.log(window.ev);
}
window.letsCountIt = function (cdtimer) {
cdtimer--;
document.getElementById('notification').innerHTML = cdtimer;
if (cdtimer == 0) {
if (window.ev === true) {
alert('over');
} else {
alert('not over');
}
} else {
setTimeout(function(){letsCountIt(cdtimer);}, 1000);
}
}
Look into document.elementFromPoint . When you pass an x,y to elementFromPoint, it will return whatever element (or <body>, if no other specific element) is at that point. You can easily check if this element is the element you want.
The problem then is finding out what point your mouse is at. How to get the mouse position without events (without moving the mouse)? seems to say - don't. At least use mouseMove to track the cursor. The linked question gives examples of how to do so. (Look to the lower scoring answers, as the higher ones only got points for being snarky.)
Just want to say that, I think jQuery's mouseenter and mouseleave events would make this a lot easier, but if you can't use them, maybe this will help you.
Depending on how your page is laid out, this may not be too difficult. You can get the position of your element using the following. Quoting from another answer
element.offsetLeft and element.offsetTop are the pure javascript
properties for finding an element's position with respect to its
offsetParent; being the nearest parent element with a position of
relative or absolute
So, if your element is positioned relatively to the body, so far so good (We don't need to adjust anything).
Now, if we attach an event to the document mousemove event, we can get the current coordinates of the mouse:
document.addEventListener('mousemove', function (e) {
var x = e.clientX;
var y = e.clientY;
}, false);
Now we just need to determine if the mouse falls within the element. To do that we need the height and width of the element. Quoting from another answer
You should use the .offsetWidth and .offsetHeight properties. Note
they belong to the element, not .style.
For example:
var element = document.getElementById('element');
var height = element.offsetHeight;
var width = element.offsetWidth;
Now we have all the information we need, and just need to determine if the mouse falls within the element. We might use something like this:
var onmove = function(e) {
var minX = element.offsetLeft;
var maxX = minX + element.offsetWidth;
var minY = element.offsetTop;
var maxY = minY + element.offsetHeight;
if(e.clientX >= minX && e.clientX <= maxX)
//good horizontally
if(e.clientY >= minY && e.clientY <= maxY)
//good vertically
}
This code works, but the mouse has to be moved once after page load.
var coords;
var getMouseCoordinates = function (e) {
'use strict';
return {
x: e.clientX,
y: e.clientY
};
};
document.addEventListener('mousemove', function (e) {
coords = getMouseCoordinates(e);
}, false);
document.addEventListener('click', function () {
var divCoords = document.getElementById('t').getBoundingClientRect();
if (coords.x >= divCoords.left && coords.x <= divCoords.right && coords.y >= divCoords.top && coords.y <= divCoords.bottom) {
alert('Mouse in box');
} else {
alert('Mouse not in box');
}
}, false);
You wouldn't bind to the click event of document, but rather the finish event of your countdown.
Here's an example. Try clicking in the output window.
You don't need any coordinates or mouse events, if you know a selector for that element:
if (document.querySelector('#elementSelector:hover')) {
alert('I like it when you touch me!');
}

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