:first-child Selector

first-child selector

version added: 1.1.4jQuery(':first-child')

描述: 选择所有父级元素下的第一个子元素。

虽然:first只匹配一个单独的元素,但是:first-child选择器可以匹配超过一个:为每个父级元素匹配第一个子元素。这相当于:nth-child(1)

Example:

Finds the first span in each matched div to underline and add a hover state.

<!DOCTYPE html>
<html>
<head>
  <style>
  span { color:#008; }
  span.sogreen { color:green; font-weight: bolder; }
  </style>
  <script src="http://code.jquery.com/jquery-latest.min.js"></script>
</head>
<body>
  <div>
    <span>John,</span>
    <span>Karl,</span>
    <span>Brandon</span>

  </div>
  <div>
    <span>Glen,</span>
    <span>Tane,</span>
    <span>Ralph</span>

  </div>
<script>
    $("div span:first-child")
        .css("text-decoration", "underline")
        .hover(function () {
              $(this).addClass("sogreen");
            }, function () {
              $(this).removeClass("sogreen");
            });

</script>

</body>
</html>

Demo:

设计酷,jquery1.6 api中文手册