How to detect DIV's dimension changed?

Question

I\'ve the following sample html, there is a DIV which has 100% width. It contains some elements. While performing windows re-sizing, the inner elements may be re-positioned,

Answer 1

There is a very efficient method to determine if a element's size has been changed.

http://marcj.github.io/css-element-queries/

This library has a class ResizeSensor which can be used for resize detection.
It uses an event-based approach, so it's damn fast and doesn't waste CPU time.

Example:

new ResizeSensor(jQuery('#divId'), function(){ 
    console.log('content dimension changed');
});

Please do not use the jQuery onresize plugin as it uses setTimeout() in combination with reading the DOM clientHeight/clientWidth properties in a loop to check for changes.
This is incredible slow and inaccurate since it causes layout thrashing.

Disclosure: I am directly associated with this library.

Answer 2

I found this library to work when MarcJ's solution didn't:

https://github.com/sdecima/javascript-detect-element-resize

It's very lightweight and detects even natural resizes via CSS or simply the HTML loading/rendering.

Code sample (taken from the link):

<script type="text/javascript" src="detect-element-resize.js"></script>
<script type="text/javascript">
  var resizeElement = document.getElementById('resizeElement'),
      resizeCallback = function() {
          /* do something */
      };
  addResizeListener(resizeElement, resizeCallback);
  removeResizeListener(resizeElement, resizeCallback);
</script>

Answer 3

using Bharat Patil answer simply return false inside the your bind callback to prevent maximum stack error see example below:

$('#test_div').bind('resize', function(){
   console.log('resized');
   return false;
});

Answer 4

I DO NOT recommend setTimeout() hack as it slows down the performance! Instead, you can use DOM mutation observers for listening to Div size change.

JS:

var observer = new MutationObserver(function(mutations) {
    console.log('size changed!');
  });
  var target = document.querySelector('.mydiv');
  observer.observe(target, {
    attributes: true
  });

HTML:

<div class='mydiv'>
</div>

Here's the fiddle
Try to change the div size.

---

You can further wrap your method in the debounce method to improve efficiency. debounce will trigger your method every x milliseconds instead of triggering every millisecond the DIV is being resized.

Answer 5

Only Window.onResize exists in the specification, but you can always utilize IFrame to generate new Window object inside your DIV.

Please check this answer. There is a new little jquery plugin, that is portable and easy to use. You can always check the source code to see how it's done.

<!-- (1) include plugin script in a page -->
<script src="/src/jquery-element-onresize.js"></script>

// (2) use the detectResizing plugin to monitor changes to the element's size:
$monitoredElement.detectResizing({ onResize: monitoredElement_onResize });

// (3) write a function to react on changes:
function monitoredElement_onResize() {    
    // logic here...
}

Answer 6

i thought it couldn't be done but then i thought about it, you can manually resize a div via style="resize: both;" in order to do that you ave to click on it so added an onclick function to check element's height and width and it worked. With only 5 lines of pure javascript (sure it could be even shorter) http://codepen.io/anon/pen/eNyyVN

<div id="box" style="
                height:200px; 
                width:640px;
                background-color:#FF0066;
                resize: both;
                overflow: auto;" 
                onclick="myFunction()">
    <p id="sizeTXT" style="
                font-size: 50px;">
       WxH
    </p>
    </div>

<p>This my example demonstrates how to run a resize check on click for resizable div.</p>

<p>Try to resize the box.</p>


<script>
function myFunction() {
var boxheight = document.getElementById('box').offsetHeight;
var boxhwidth = document.getElementById('box').offsetWidth;
var txt = boxhwidth +"x"+boxheight;
document.getElementById("sizeTXT").innerHTML = txt;
}
</script>