How to get the “declared” CSS value, not the computed CSS value

Tags: javascript,css

Problem :

How can we use JavaScript to get the value of the declared CSS value (like the value that shows up when inspecting an element using Chrome's inspector? Everything I try and search for on the web seems to only want to give the computed value.

For my specific use case I want to know what the width will be at the end of a CSS transition, which is set in the stylesheet, not inline. When I check for the width using JavaScript, I get the computed width, which at the time of retrieval in the script is at the beginning of the transition, so shows me 0 even though in 300ms it will be a declared width like 320px.

Solution :

I think this is what you're after:

$('#widen').on('click', function(e){
    $('#prefetch').text('The div will be: ' + getWidth('wider'));

function getWidth(className){
    for (var s = 0; s < document.styleSheets.length; s++){
        var rules = document.styleSheets[s].rules || document.styleSheets[s].cssRules; console.log(rules);
        for (var r = 0; r < rules.length; r++){
            var rule = rules[r]; console.log(rule);
            if (rule.selectorText == '.'+className){
    return undefined;
.example {
    width: 100px;
    background-color: #ccc;
    border: 1px solid black;
.wider {
    width: 320px;
    -webkit-transition: width 5s;
    -moz-transition: width 5s;
    -o-transition: width 5s;
    transition: width 5s;
<script src=""></script>

<div class="example">This is a simple container.</div>
<button id="widen" type="button">Widen</button>
<span id="prefetch"></span>

Keep in mind, I believe this still falls victim to cross-domain preventions (if the CSS is hosted on a CDN/other domain, you won't be able to retrieve the styleSheet, and, therefore, not be able to access then eventual width.

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