# jQuery UI addClass

## Overview

[edit]

### addClass( class, [duration] )

Adds the specified class to each of the set of matched elements with an optional transition between the states.

### Dependencies

- Effects Core

### Example

- Demo
- View Source

Adds the class 'selected' to the matched elements with a one second transition.

    $("p").click(function () {
          $(this).addClass("selected", 1000);
        });

    <!DOCTYPE html>
    <html>
    <head>
      <link href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/themes/base/jquery-ui.css" rel="stylesheet" type="text/css"/>
      <script src="http://ajax.googleapis.com/ajax/libs/jquery/1.5/jquery.min.js"></script>
      <script src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8/jquery-ui.min.js"></script>
      <script src="http://ui.jquery.com/latest/ui/effects.core.js"></script>
    <style type="text/css">
      p { cursor: pointer; font-size: 1.2em; }
      .selected { color:red; }
    </style>
      <script>
      $(document).ready(function() {
        $("p").click(function () {
          $(this).addClass("selected", 1000);
        });
      });
      </script>
    </head>
    <body style="font-size:62.5%;">
      <p>Click me to add a 'selected' class.</p>
    <p>Click me to add a 'selected' class.</p>
    <p>Click me to add a 'selected' class.</p>
    </body>
    </html>

## Arguments

- ### class

  Type:
    String

  One CSS class to add to the elements.

- ### duration

  Type:
    String, Number
  Optional

  A string representing one of the three predefined speeds ("slow", "normal", or "fast") or the number of milliseconds to run the animation (e.g. 1000).