jQuery.isFunction()

jQuery.isFunction( obj )

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

jQuery.isFunction( obj )

version added: 1.2

obj

Object to test whether or not it is a 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

Example 1

Test a few parameter examples.

    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);
    });

The output of the code above will be:

Try it yourself

Full source:

<!DOCTYPE html>
<html>
<head>
<script src="http://code.jquery.com/jquery-latest.js"></script>
  <script>
  $(document).ready(function(){
    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>
  <style>
  div { color:blue; margin:2px; font-size:14px; }
  span { color:red; }
  </style>
</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>  
</body>
</html>

Try it yourself

Example 2

Finds out if the parameter is a function.

$.isFunction(function(){});

The output of the code above will be:

true

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jQuery.isFunction()

jQuery.isFunction( obj )

jQuery.isFunction( obj )

Examples

Example 1

Example 2

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