返回值:Integerwidth()

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.

$(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.

示例:

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

<!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="jquery.min.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>
演示:

返回值:jQuerywidth(value)

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 was specified (like 'em' or '%') then "px" is concatenated to the value.

Note that .width('value') sets the width of the box in accordance with the CSS box-sizing property. Changing this property to border-box will cause this function to change the outerWidth of the box instead of the content width.

示例:

To set the width of each div on click to 30px plus a color change.

<!DOCTYPE html>
<html>
<head>
<style>
  div { width:70px; height:50px; float:left; margin:5px;
        background:red; cursor:pointer; }
  </style>
<script src="jquery.min.js"></script>
</head>
<body>

<div></div>
  <div>d</div>

  <div>d</div>
  <div>d</div>
  <div>d</div>

<script>



    $("div").one('click', function () {
      $(this).width(30)
             .css({cursor:"auto", "background-color":"blue"});
    });


</script>
</body>
</html>
演示: