Description

The callbacks.has() method determines whether a supplied callback is in a list.

---

This method has the form:

callbacks.has(callback)

Parameter	Description
callback	Specifies the callback to search for

Return Value

This form returns a Boolean.

Examples

Use the callbacks.has() method to check if a callback list contains a specific callback:

// a sample logging function to be added to a callbacks list
var foo = function(value1, value2){
  console.log('Received:' + value1 + ',' + value2);
}

// a second function which will not be added to the list
var bar = function(value1, value2){
  console.log( 'foobar');
}

var callbacks = $.Callbacks();

// add the log method to the callbacks list
callbacks.add(foo);

// determine which callbacks are in the list
console.log(callbacks.has(foo)); // true
console.log(callbacks.has(bar)); // false