Примеры для jQuery .is()

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Shows a few ways is() can be used inside an event handler.

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<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>is demo</title>
  <style>
  div {
    width: 60px;
    height: 60px;
    margin: 5px;
    float: left;
    border: 4px outset;
    background: green;
    text-align: center;
    font-weight: bolder;
    cursor: pointer;
  }
  .blue {
    background: blue;
  }
  .red {
    background: red;
  }
  span {
    color: white;
    font-size: 16px;
  }
  p {
    color: red;
    font-weight: bolder;
    background: yellow;
    margin: 3px;
    clear: left;
    display: none;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<div></div>
<div class="blue"></div>
<div></div>
<div class="red"></div>
<div><br/><span>Peter</span></div>
<div class="blue"></div>
<p>&nbsp;</p>
 
<script>
$( "div" ).one( "click", function() {
  if ( $( this ).is( ":first-child" ) ) {
    $( "p" ).text( "It's the first div." );
  } else if ( $( this ).is( ".blue,.red" ) ) {
    $( "p" ).text( "It's a blue or red div." );
  } else if ( $( this ).is( ":contains('Peter')" ) ) {
    $( "p" ).text( "It's Peter!" );
  } else {
    $( "p" ).html( "It's nothing <em>special</em>." );
  }
  $( "p" ).hide().slideDown( "slow" );
  $( this ).css({
    "border-style": "inset",
    cursor: "default"
  });
});
</script>
 
</body>
</html>

Демонстрация:

Returns true, because the parent of the input is a form element.

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<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>is demo</title>
  <style>
  div {
    color: red;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<form>
  <input type="checkbox">
</form>
<div></div>
 
<script>
var isFormParent = $( "input[type='checkbox']" ).parent().is( "form" );
$( "div" ).text( "isFormParent = " + isFormParent );
</script>
 
</body>
</html>

Демонстрация:

Returns false, because the parent of the input is a p element.

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<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>is demo</title>
  <style>
  div {
    color: red;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<form>
  <p><input type="checkbox"></p>
</form>
<div></div>
 
<script>
var isFormParent = $( "input[type='checkbox']" ).parent().is( "form" );
$( "div" ).text( "isFormParent = " + isFormParent );
</script>
 
</body>
</html>

Демонстрация:

Checks against an existing collection of alternating list elements. Blue, alternating list elements slide up while others turn red.

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<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>is demo</title>
  <style>
  li {
    cursor: pointer;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<ul id="browsers">
  <li>Chrome</li>
  <li>Safari</li>
  <li>Firefox</li>
  <li>Opera</li>
</ul>
 
<script>
var alt = $( "#browsers li:nth-child(2n)" ).css( "background", "#0ff" );
$( "li" ).click(function() {
  var li = $( this );
  if ( li.is( alt ) ) {
    li.slideUp();
  } else {
    li.css( "background", "red" );
  }
});
</script>
 
</body>
</html>

Демонстрация:

An alternate way to achieve the above example using an element rather than a jQuery object. Checks against an existing collection of alternating list elements. Blue, alternating list elements slide up while others turn red.

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<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>is demo</title>
  <style>
  li {
    cursor: pointer;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<ul id="browsers">
  <li>Chrome</li>
  <li>Safari</li>
  <li>Firefox</li>
  <li>Opera</li>
</ul>
 
<script>
var alt = $( "#browsers li:nth-child(2n)" ).css( "background", "#0ff" );
$( "li" ).click(function() {
  if ( alt.is( this ) ) {
    $( this ).slideUp();
  } else {
    $( this ).css( "background", "red" );
  }
});
</script>
 
</body>
</html>

Демонстрация: