jQuery jQuery.isFunction()

.jQuery.isFunction()

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.

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>

Example : Finds out if the parameter is a function.

<!DOCTYPE html>
<html>
<head>
<script src='http://code.jquery.com/jquery-latest.js'></script>
</head>
<body>

<script>
$.isFunction(function() {});
</script>
</body>
</html>