Difference between var and this in Javascript functions?

Question

var tools = {};

tools.triangle = function() {
    var originX = 0;
    var originY = 0;
}

 

var tools = {};

tools.triangle =         


        

Answer 1

In the first example, X and Y both exist as local variables to the closure saved in the variable triangle.

In the second example, X and Y exist as variables to the object tools.triangle because of the use of this.