[ thisScope ], [ arg1 ], [ arg2 ], [ ... ] ) in ECMAScript 262

Call the function/method, optionally setting a new scope for this and passing in parameters.


thisScope Object [optional] The object to use as thi
arg1 Object [optional] The first argument to pass.
arg2 Object [optional] The second argument to pass.
... Object [optional] etc.
Return Type


Like the apply method, this method of a function object allows you to invoke the function code, while specifying a different scope for it to run in. Unlike that method, parameters to be passed to the called function exist as a comma-separate list, not as an array of parameters.

A real-world example where this can be useful is to simulate multiple interfaces to a single class. (ECMAScript supports hierarchical inheritance amongst user-created classes, but does not allow a single class to inherit from multiple parents.) In the following example, the Rectangle class wants to be able to call methods from the Polygon class, but (for no reason other than to illustrate this method) does not inherit from that class.

function Polygon(){ }
    return this.calculateArea()*sweepDistance;

function Rectangle(width,length){
    return this.width*this.length;

var obj1 = new Rectangle(10,5);
var volume =,4);
// ** volume is 200