返回值:Stringcss(propertyName)

Get the value of a style property for the first element in the set of matched elements.

The .css() method is a convenient way to get a style property from the first matched element, especially in light of the different ways browsers access most of those properties (the getComputedStyle() method in standards-based browsers versus the currentStyle and runtimeStyle properties in Internet Explorer) and the different terms browsers use for certain properties. For example, Internet Explorer's DOM implementation refers to the float property as styleFloat, while W3C standards-compliant browsers refer to it as cssFloat. The .css() method accounts for such differences, producing the same result no matter which term we use. For example, an element that is floated left will return the string left for each of the following three lines:

  1. $('div.left').css('float');
  2. $('div.left').css('cssFloat');
  3. $('div.left').css('styleFloat');

Also, jQuery can equally interpret the CSS and DOM formatting of multiple-word properties. For example, jQuery understands and returns the correct value for both .css('background-color') and .css('backgroundColor').

Shorthand CSS properties (e.g. margin, background, border) are not supported. For example, if you want to retrieve the rendered margin, use: $(elem).css('marginTop') and $(elem).css('marginRight'), and so on.

示例:

To access the background color of a clicked div.

<!DOCTYPE html>
<html>
<head>
<style>
div { width:60px; height:60px; margin:5px; float:left; }
  </style>
<script src="jquery.min.js"></script>
</head>
<body>


<span id="result">&nbsp;</span>
<div style="background-color:blue;"></div>
<div style="background-color:rgb(15,99,30);"></div>

<div style="background-color:#123456;"></div>
<div style="background-color:#f11;"></div>

<script>


$("div").click(function () {
  var color = $(this).css("background-color");
  $("#result").html("That div is <span style='color:" +
                     color + ";'>" + color + "</span>.");
});



</script>
</body>
</html>
演示:

返回值:jQuerycss(propertyName, value)

Set one or more CSS properties for the set of matched elements.

As with the .attr() method, the .css() method makes setting properties of elements quick and easy. This method can take either a property name and value as separate parameters, or a single map of key-value pairs (JavaScript object notation).

Also, jQuery can equally interpret the CSS and DOM formatting of multiple-word properties. For example, jQuery understands and returns the correct value for both .css({'background-color': '#ffe', 'border-left': '5px solid #ccc'}) and .css({backgroundColor: '#ffe', borderLeft: '5px solid #ccc'}). Notice that with the DOM notation, quotation marks around the property names are optional, but with CSS notation they're required due to the hyphen in the name.

As with .attr(), .css() allows us to pass a function as the property value: 

$('div.example').css('width', function(index) {
  return index * 50;
});

This example sets the widths of the matched elements to incrementally larger values.

示例:

To change the color of any paragraph to red on mouseover event.

<!DOCTYPE html>
<html>
<head>
<style>
  p { color:blue; width:200px; font-size:14px; }
  </style>
<script src="jquery.min.js"></script>
</head>
<body>


  <p>Just roll the mouse over me.</p>

  <p>Or me to see a color change.</p>
  

<script>


  $("p").mouseover(function () {
    $(this).css("color","red");
  });


</script>
</body>
</html>
演示:

示例:

To highlight a clicked word in the paragraph.

<!DOCTYPE html>
<html>
<head>
<style>
  p { color:blue; font-weight:bold; cursor:pointer; }
  </style>
<script src="jquery.min.js"></script>
</head>
<body>


<p>
  Once upon a time there was a man
  who lived in a pizza parlor. This
  man just loved pizza and ate it all 
  the time.  He went on to be the
  happiest man in the world.  The end.
</p>

<script>


  var words = $("p:first").text().split(" ");
  var text = words.join("</span> <span>");
  $("p:first").html("<span>" + text + "</span>");
  $("span").click(function () {
    $(this).css("background-color","yellow");
  });



</script>
</body>
</html>
演示:

示例:

To set the color of all paragraphs to red and background to blue:

<!DOCTYPE html>
<html>
<head>
<style>
  p { color:green; }
</style>
<script src="jquery.min.js"></script>
</head>
<body>


  <p>Move the mouse over a paragraph.</p>
  <p>Like this one or the one above.</p>


<script>


  $("p").hover(function () {
    $(this).css({'background-color' : 'yellow', 'font-weight' : 'bolder'});
  }, function () {
    var cssObj = {
      'background-color' : '#ddd',
      'font-weight' : '',
      'color' : 'rgb(0,40,244)'
    }
    $(this).css(cssObj);
  });


</script>
</body>
</html>
演示:

示例:

Increase the size of a div when you click it:

<!DOCTYPE html>
<html>
<head>
<style>
  div { width: 20px; height: 15px; background-color: #f33; }
  </style>
<script src="jquery.min.js"></script>
</head>
<body>


  <div>click</div>
  <div>click</div>


<script>


  $("div").click(function() {
    $(this).css({
      width: function(index, value) {
        return parseFloat(value) * 1.2;
      }, 
      height: function(index, value) {
        return parseFloat(value) * 1.2;
      }

    });
  });


</script>
</body>
</html>
演示: