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jQuery中focusin()和focus()、find()和children()的差别

jQuery中focus()和focusin()、focus()和children()的差别

focus()和focusin()

focus()和focusin()的差别在于focusin()支持事件的冒泡。以下举例说明:

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>focusin demo</title>
  <style>
  span {
    display: none;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>

<p><input type="text"> <span>focusin fire</span></p>
<p><input type="password"> <span>focusin fire</span></p>

<script>
$( "p" ).focusin(function() {
  $( this ).find( "span" ).css( "display", "inline" ).fadeOut( 1000 );
});
</script>

</body>
</html>

当我们点击输入框时。其获得焦点。导致获得焦点事件向上冒泡,使得p标签触发获得焦点事件,而focus()并不支持事件冒泡,相同地。focusout()支持事件冒泡,而blur()不支持。

find()和children()

find()和children()的差别在于find()向下追溯多级子节点,而children()仅仅向下追溯一级子节点。find()和children()相同的地方是他们在寻找子节点时都不包括自身节点。

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
    <style type="text/css">
        p{
            font-size: 20px;
            width: 200px;
            color: blue;
            font-weight: bold;
            margin: 0 10px;
          }
          .hilite {
            background: yellow;
          }
    #test{
        font-weight: bolder;
    }
    </style>
</head>
<body>
<ul class="level-1">
  <li class="item-i">I</li>
  <li class="item-ii">II
    <ul class="level-2">
      <li class="item-a">A</li>
      <li class="item-b">B
        <ul class="level-3">
          <li class="item-1">1</li>
          <li class="item-2">2</li>
          <li class="item-3">3</li>
        </ul>
      </li>
      <li class="item-c">C</li>
    </ul>
  </li>
  <li class="item-iii">III</li>
</ul>
    <script src="jquery-2.1.4.js"></script>
    <script>
        $( "li.item-ii" ).find( "li" ).css( "background-color", "red" );
    </script>

</body>
</html>

倘若将上例中的find()替换为children(),会得到不同的结果。

<script type="text/javascript"> $(function () { $(‘pre.prettyprint code‘).each(function () { var lines = $(this).text().split(‘\n‘).length; var $numbering = $(‘
    ‘).addClass(‘pre-numbering‘).hide(); $(this).addClass(‘has-numbering‘).parent().append($numbering); for (i = 1; i <= lines; i++) { $numbering.append($(‘
  • ‘).text(i)); }; $numbering.fadeIn(1700); }); }); </script>

jQuery中focusin()和focus()、find()和children()的差别