Summary of the call () and apply () Methods for function objects in JavaScript

In JavaScript, each function has a call () and an apply () method, with the following examples:

First define an Some_obj object that has a say () Method:

var some_obj={
Name: ' Ninja ',
Say:function (WHO) {
Return ' Haya ' + who + ', I am a ' + this.name;
}
};

Call Some_obj.say (' Dude ');

Output: "Haya Dude, I am a Ninja"

Create an object again

var my_obj={name: ' Scripting guru '};

We now want to call the Say () method in Some_obj as a method of My_obj itself, in which case you can try the object method in the Say () function called ()

Some_obj.say.call (my_obj, ' Dude ');

Output: "Haya Dude, I am a Scripting guru";

In addition, if we do not pass the object to the first argument of call (), or to it is null, the calling object is defaulted to the global object (see note:);

Note: This refers to the global object, which in effect modifies the object function's this value through the first parameter of call;

If you use the object method apply ();

Some_obj.say.apply (my_obj,[' Dude ');

Output: "Haya Dude, I am a Scripting guru";

Thus, apply () and call () are basically the same, the difference is the transfer of the form of parameters, apply () The Parameter form is an array;

Pass more parameters: Some_obj.someMethod.call (my_obj, ' A ', ' B ', ' C ');

Summary of the call () and apply () Methods for function objects in JavaScript