# callbacks.has()

## callbacks.has ( callback ) Returns: Boolean version added: 1.7

- callback
  Type: Function
  The callback to search for.

Description: Determine whether a supplied callback is in a list

## Examples:

#### Example: Use callbacks.has() 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