jQuery.isFunction()

jQuery.isFunction() Returns: boolean

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

  • version added: 1.2jQuery.isFunction()

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>
<head>
  <style>
  div { color:blue; margin:2px; font-size:14px; }
  span { color:red; }
  </style>
  <script src="http://code.jquery.com/jquery-latest.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 funcion.

$.isFunction(function(){});

Result:

true