# jQuery.fn.extend()

## jQuery.fn.extend ( object ) Returns: Object version added: 1.0

- object
  Type: Object
  An object to merge onto the jQuery prototype.

Description: Merge the contents of an object onto the jQuery prototype to provide new jQuery instance methods.

The `jQuery.fn.extend()` method extends the jQuery prototype (`$.fn`) object to provide new methods that can be chained to the `jQuery()` function.

## Examples:

#### Example: Add two methods to the jQuery prototype ($.fn) object and then use one of them.

    <!doctype html>
    <html lang="en">
    <head>
      <meta charset="utf-8">
      <title>css demo</title>

      <style>

      label {
        display: block;
        margin: .5em;
      }

      </style>

      <script src="//code.jquery.com/jquery-1.10.2.js"></script>
    </head>
    <body>

    <label><input type="checkbox" name="foo"> Foo</label>
    <label><input type="checkbox" name="bar"> Bar</label>

    <script>

    jQuery.fn.extend({
      check: function() {
        return this.each(function() {
          this.checked = true;
        });
      },
      uncheck: function() {
        return this.each(function() {
          this.checked = false;
        });
      }
    });

    // Use the newly created .check() method
    $( "input[type='checkbox']" ).check();

    </script>

    </body>
    </html>

#### Demo: