# jQuery.isFunction()

## jQuery.isFunction ( obj ) Returns: boolean version added: 1.2

- obj
  Type: PlainObject
  Object to test whether or not it is a function.

Description: Determine if the argument passed is a Javascript function object.

Note: As of jQuery 1.3, functions provided by the browser like `alert()` and DOM element methods like `getAttribute()` are not guaranteed to be detected as functions in browsers such as Internet Explorer.

## Examples:

#### Example: Test a few parameter examples.

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

      <style>

      div {
        color: blue;
        margin: 2px;
        font-size: 14px;
      }
      span {
        color: red;
      }

      </style>

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

    <div>jQuery.isFunction( objs[ 0 ] ) = <span></span></div>
    <div>jQuery.isFunction( objs[ 1 ] ) = <span></span></div>
    <div>jQuery.isFunction( objs[ 2 ] ) = <span></span></div>
    <div>jQuery.isFunction( objs[ 3 ] ) = <span></span></div>
    <div>jQuery.isFunction( objs[ 4 ] ) = <span></span></div>

    <script>

    function stub() {}
    var objs = [
      function() {},
      { x:15, y:20 },
      null,
      stub,
      "function"
    ];

    jQuery.each( objs, function( i ) {
      var isFunc = jQuery.isFunction( objs[ i ]);
      $( "span" ).eq( i ).text( isFunc );
    });

    </script>

    </body>
    </html>

#### Demo:

#### Example: Finds out if the parameter is a function.

    $.isFunction(function() {});