Determines if its argument is callable as a function.

jQuery.isFunction(value)🡢 boolean

value AnythingThe 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.

Test a few parameter examples.

<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>
div {
  color: blue;
  margin: 2px;
  font-size: 14px;
span {
  color: red;
function stub() {}
var objs = [function () {}, { x: 15, y: 20 }, null, stub, "function"];

jQuery.each(objs, function (i) {
  var isFunc = jQuery.isFunction(objs[i]);

Finds out if the parameter is a function.

$.isFunction(function () {});

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