Get the current computed width for the first element in the set of matched elements or set the width of every matched element.

Contents:

.width()Returns: Integer

Description: Get the current computed width for the first element in the set of matched elements.

The difference between .css(width) and .width() is that the latter returns a unit-less pixel value (for example, 400) while the former returns a value with units intact (for example, 400px). The .width() method is recommended when an element's width needs to be used in a mathematical calculation.

This method is also able to find the width of the window and document.

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$(window).width(); // returns width of browser viewport
$(document).width(); // returns width of HTML document

Note that .width() will always return the content width, regardless of the value of the CSS box-sizing property.

Example:

Show various widths. Note the values are from the iframe so might be smaller than you expected. The yellow highlight shows the iframe body.

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<!DOCTYPE html>
<html>
<head>
<style>
body { background:yellow; }
button { font-size:12px; margin:2px; }
p { width:150px; border:1px red solid; }
div { color:red; font-weight:bold; }
</style>
<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
<button id="getp">Get Paragraph Width</button>
<button id="getd">Get Document Width</button>
<button id="getw">Get Window Width</button>
<div>&nbsp;</div>
<p>
Sample paragraph to test width
</p>
<script>
function showWidth(ele, w) {
$("div").text("The width for the " + ele +
" is " + w + "px.");
}
$("#getp").click(function () {
showWidth("paragraph", $("p").width());
});
$("#getd").click(function () {
showWidth("document", $(document).width());
});
$("#getw").click(function () {
showWidth("window", $(window).width());
});
</script>
</body>
</html>

Demo:

.width( value )Returns: jQuery

Description: Set the CSS width of each element in the set of matched elements.

When calling .width("value"), the value can be either a string (number and unit) or a number. If only a number is provided for the value, jQuery assumes a pixel unit. If a string is provided, however, any valid CSS measurement may be used for the width (such as 100px, 50%, or auto). Note that in modern browsers, the CSS width property does not include padding, border, or margin, unless the box-sizing CSS property is used.

If no explicit unit is specified (like "em" or "%") then "px" is assumed.

Note that .width("value") sets the content width of the box regardless of the value of the CSS box-sizing property.

Example:

Change the width of each div the first time it is clicked (and change its color).

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<!DOCTYPE html>
<html>
<head>
<style>
div { width: 70px; height: 50px; float:left; margin: 5px;
background: red; cursor: pointer; }
.mod { background: blue; cursor: default; }
</style>
<script src="http://code.jquery.com/jquery-latest.js"></script>
</head>
<body>
<div>d</div>
<div>d</div>
<div>d</div>
<div>d</div>
<div>d</div>
<script>
(function() {
var modWidth = 50;
$("div").one('click', function () {
$(this).width(modWidth).addClass("mod");
modWidth -= 8;
});
})();
</script>
</body>
</html>

Demo: