DIV onresize

There is no support via native JavaScript to track changes in the width and height of a DIV. So, in the following example, we will show a simple implementation to track the changes in dimensions of a DIV using LemonadeJS.


Tracking changes in a DIV dimensions example

Source code

<script src="https://lemonadejs.net/v2/lemonade.js"></script>
<div id='root'></div>
var Width = (function() {
    var self = {};

    self.init = function(element) {
        // Initial values
        var w = element.offsetWidth;
        var h = element.offsetHeight;

        // Track the changes
        element.onmousemove = function(e) {
            if (e.which) {
                if (w !== element.offsetWidth || h !== element.offsetHeight) {
                    w = element.offsetWidth;
                    h = element.offsetHeight;

                    // Update dimensions label
                    self.dimensions = w + ',' + h;

    self.onresize = function(element) {
        console.log('DIV has new dimensions');

    // Component template
    var template = `<div class="resizable" @ready="self.init(this)">
        On resize on DIV elements: <span>{{self.dimensions}}</span>

    return lemonade.element(template, self);

lemonade.render(Width, document.getElementById('root'));

See this example on codesandbox

A pure vanilla implementation

Although this site is dedicated to LemonadeJS, for education purposes, we present you with a pure javascript vanilla implementation using onmousemove.

Pure vanilla implementation

DIV onresize example on jsfiddle

Source code

var move = function(e) {
    if ((e.w && e.w !== e.offsetWidth) || (e.h && e.h !== e.offsetHeight)) {
        new Function(e.getAttribute('onresize')).call(e);
    e.w = e.offsetWidth;
    e.h = e.offsetHeight;
var resize = function() {
<div class='resizable' onresize="resize(this)" onmousemove="move(this)">
Pure vanilla implementation

The CSS used for this section

If you wish to test the examples of this section, please copy this CSS to your project.

.resizable {
    resize: both;
    overflow: auto;
    width: 200px;
    border: 1px solid black;
    padding: 20px;