console.log, that prints number of milliseconds since last console.log invocation

console.timed_log.js

console.timed_log = function() {
        var args = Array.prototype.splice.call(arguments, 0);
        var time = +new Date();
        var diff = time - (this._time || time);
        args.unshift(diff);
        console.log.apply(console, args);
        this._time = time;
      };