:hidden selector

Selects all elements that are hidden.

Elements can be considered hidden for several reasons:

They have a CSS display value of none.
They are form elements with type="hidden".
Their width and height are explicitly set to 0.
An ancestor element is hidden, so the element is not shown on the page.

Elements with visibility: hidden or opacity: 0 are considered to be visible, since they still consume space in the layout. During animations that hide an element, the element is considered to be visible until the end of the animation.

Elements that are not in a document are not considered to be visible; jQuery does not have a way to know if they will be visible when appended to a document since it depends on the applicable styles.

This selector is the opposite of the :visible selector. So, every element selected by :hidden isn't selected by :visible and vice versa.

During animations to show an element, the element is considered to be visible at the start of the animation.

How :hidden is determined was changed in jQuery 1.3.2. An element is assumed to be hidden if it or any of its parents consumes no space in the document. CSS visibility isn't taken into account (therefore $( elem ).css( "visibility", "hidden" ).is( ":hidden" ) == false). The release notes outline the changes in more detail.

Because :hidden is a jQuery extension and not part of the CSS specification, queries using :hidden cannot take advantage of the performance boost provided by the native DOM querySelectorAll() method. To achieve the best performance when using :hidden to select elements, first select the elements using a pure CSS selector, then use .filter(":hidden").
Using this selector heavily can have performance implications, as it may force the browser to re-render the page before it can determine visibility. Tracking the visibility of elements via other methods, using a class for example, can provide better performance.

jQuery( ":hidden" )

version added: 1.0

Examples:

Shows all hidden divs and counts hidden inputs.

<!doctype html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <title>hidden demo</title>
  <style>
  div {
    width: 70px;
    height: 40px;
    background: #e7f;
    margin: 5px;
    float: left;
  }
  span {
    display: block;
    clear: left;
    color: red;
  }
  .starthidden {
    display: none;
  }
  </style>
  <script src="https://code.jquery.com/jquery-1.10.2.js"></script>
</head>
<body>
 
<span></span>
<div></div>
<div style="display:none;">Hider!</div>
<div></div>
 
<div class="starthidden">Hider!</div>
<div></div>
 
<form>
  <input type="hidden">
  <input type="hidden">
  <input type="hidden">
</form>
 
<span></span>
 
<script>
// In some browsers :hidden includes head, title, script, etc...
var hiddenElements = $( "body" ).find( ":hidden" ).not( "script" );
 
$( "span:first" ).text( "Found " + hiddenElements.length + " hidden elements total." );
$( "div:hidden" ).show( 3000 );
$( "span:last" ).text( "Found " + $( "input:hidden" ).length + " hidden inputs." );
</script>
 
</body>
</html>

Links:

http://api.jquery.com/hidden-selector

doc_jQuery

2016-03-27 13:48:25

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