## jQuery.isFunction( value )Returns: boolean version deprecated: 3.3

Description: Determines if its argument is callable as a function.

- #### version added: 1.2 jQuery.isFunction( value )

  - value
    Type: Anything
    The value to be tested.

As of jQuery 3.3, `jQuery.isFunction()` has been deprecated. In most cases, its use can be replaced by `typeof x === "function"`.

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:

Test a few parameter examples.

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 |
    <!doctype html><html lang="en"><head>  <meta charset="utf-8">  <title>jQuery.isFunction demo</title>  <style>  div {    color: blue;    margin: 2px;    font-size: 14px;  }  span {    color: red;  }  </style>  <script src="https://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:

Finds out if the parameter is a function.

1 |
    $.isFunction(function() {});

#### Result:

1 |
    true