Question

    var someObject = {
someArray : new Array(),

someInt : 0,

Total: function(){

this.someInt = 0;//we used "this" keyword here, why?Cant we just say "someInt = 0"?

for(var i=0;i<this.someArray.length;i++){//and here..

var c = this.someArray[i];//again we use "this"

this.someInt += c.value;//also here
}

so why did we use “this” keyword? cant we just type the name of the variable?

Answer 1

The this keyword refers to the object on whose behalf the call is made later on, i.e. if you call the function like this:

someObject.Total()

then this will refer to someObject inside the function. Thanks to this keyword the function can modify someInt and read from someArray which are members of someObject. If you dropped this from the function body, all those references would be to global variables or variables local to the function body.