I wanna know how to trigger an event when a div changes its height or any css attribute.
I have a div with id = mainContent. I want jquery to automatically trigger an event when it changes its height. I did something like this:
$("#mainContent").change('height', function() {
$("#separator").css('height', $("#mainContent").height());
});
I know its wrong.
Here's my whole code (I pasted all of it because I can't get into jsfiddle for some reason I don't know):
<html>
<head>
<style type="text/css">
html, body {
width: 100%;
height: 100%;
margin: 0;
padding: 0;
}
#separator {
border-right: 1px solid black;
}
</style>
<script type="text/javascript" src="jquery1.6.4min.js"> </script>
<script type="text/javascript">
$(document).ready(function() {
$("#separator").css('height', $("body").height());
});
$(function() {
$("#btnSample1").click(function() {
$("#mainContent").css('height', '400px');
$("#mainContent").css('width', '600px');
$("#mainContent").css('background-color', '#F0F0F0');
});
$("#btnSample2").click(function() {
$("#mainContent").css('height', '1600px');
$("#mainContent").css('width', '700px');
$("#mainContent").css('background-color', '#F0F0F0');
});
$("#mainContent").change('height', function() {
$("#separator").css('height', $("#mainContent").height());
});
});
</script>
</head>
<body>
<table style="width: 100%;">
<tr>
<td valign="top" style="width: 19%;">
<table id="mainMenu">
<tr><td><input id="btnSample1" type="button" value="Sample 1" /></td></tr>
<tr><td><input id="btnSample2" type="button" value="Sample 2" /></td></tr>
</table>
</td>
<td valign="top" style="width: 1%;" >
<div id="separator"></div>
</td>
<td valign="top" style="width: 80%;">
<div id="mainContent"></div>
</td>
</tr>
</table>
</body>
</html>
I am trying to adjust the height of the div id=separator based on the height of mainContent whenever the height of mainContent changes.
PS: In this case I know I can use the button event to do this but I want the div to trigger the event when the height is changed. Please help. Thanks in advance.
This question is related to
javascript
jquery
css
First, There is no such css-changes event out of the box, but you can create one by your own, as onchange is for :input elements only. not for css changes.
There are two ways to track css changes.
DOMAttrModified mutation event. But it's deprecated, so I'll skip on it.First way:
var $element = $("#elementId");
var lastHeight = $("#elementId").css('height');
function checkForChanges()
{
if ($element.css('height') != lastHeight)
{
alert('xxx');
lastHeight = $element.css('height');
}
setTimeout(checkForChanges, 500);
}
Second way:
$('#mainContent').bind('heightChange', function(){
alert('xxx');
});
$("#btnSample1").click(function() {
$("#mainContent").css('height', '400px');
$("#mainContent").trigger('heightChange'); //<====
...
});
If you control the css changes, the second option is a lot more elegant and efficient way of doing it.
Documentations:
Please don't use techniques described in other answers here. They are either not working with css3 animations size changes, floating layout changes or changes that don't come from jQuery land. You can use a resize-detector, a event-based approach, that doesn't waste your CPU time.
https://github.com/marcj/css-element-queries
It contains a ResizeSensor class you can use for that purpose.
new ResizeSensor(jQuery('#mainContent'), function(){
console.log('main content dimension changed');
});
Disclaimer: I wrote this library
Another simple example.
For this sample we can use 100x100 DIV-box:
<div id="box" style="width: 100px; height: 100px; border: solid 1px red;">
// Red box contents here...
</div>
And small jQuery trick:
<script type="text/javascript">
jQuery("#box").bind("resize", function() {
alert("Box was resized from 100x100 to 200x200");
});
jQuery("#box").width(200).height(200).trigger("resize");
</script>
Steps:
That's all. ;-)
For future sake I'll post this. If you do not need to support < IE11 then you should use MutationObserver.
Here is a link to the caniuse js MutationObserver
Simple usage with powerful results.
var observer = new MutationObserver(function (mutations) {
//your action here
});
//set up your configuration
//this will watch to see if you insert or remove any children
var config = { subtree: true, childList: true };
//start observing
observer.observe(elementTarget, config);
When you don't need to observe any longer just disconnect.
observer.disconnect();
Check out the MDN documentation for more information
Source: Stackoverflow.com