无法使用此运算符调用javascript函数

Question

why this operator is not working with this javascript object

var data = {
    opt: null,

    ajaxCall: function () {
        //my ajax call code here

        this.fillDataInDiv(); //This statement is not working
        data.fillDataInDiv(); //this is working why ?
    },

    fillDataInDiv: function () {
        //code to fill data in div
    }
} 

can someone explain, what is the difference between these two statement

1. this.fillDataInDiv(); // and why this statement is not working
2. data.fillDataInDiv();

Answer 1

The data above behaves more like a namespace, not an object.

Consider this :

var data = function() {};

var dataObject = new data();

Now if you have to add methods to this class:

var data = function() {

    // Equivalent to public members

    this.opt = null;

    // Equivalent to public methods :

    this.ajaxCall = function () {    
        this.fillDataInDiv(); 
    };

    this.fillDataInDiv = function () {
        //code to fill data in div
    };
}

Answer 2

This is depending on the way the ajaxCall be called.

For simple, it depends on the caller .

If you use data.ajaxCall(); , then yes, this refers to the data .

But if the caller is not data , then this refers the caller but not the data .

For example:

var func = data.ajaxCall;
func(); // this inside data.ajaxCall refers to the window object.