Ugly Timer object

dumbTimer.js

function simpleTimer(){
    var that = this;
	    this.obj = {
		    open_time: 0
			,close_time: 0
			,total_time: 0
		};

		this.intTimer = {};

        this.meth = function(fx){
		    var current = new Date().getTime();
            that.obj.total_time = (current - that.obj.open_time);
            fx(that.obj);
        };

        this.start = function(fx){
            this.obj.open_time = new Date().getTime();
            this.intTimer = setInterval(function(){that.meth(fx);},100);
        };

        this.stop = function(){
            clearInterval(this.intTimer);
        }
}