performance timer

gistfile1.js

var performance = {
        map: {},
        start: function(key) {
            this.map[key] = {};
            this.map[key].start = Date.now();
        },
        end: function(key) {
            this.map[key].end = Date.now();
        },
        display: function(key) {
            var time = (this.map[key].end - this.map[key].start)/1000 + ' seconds';
            delete this.map[key];
            return time;
        }
    };