gistfile1.txt

var Runner = function() {
	this.canvas = document.getElementsByTagName('canvas')[0];
	this.event = document.createEvent('Event');
	this.eventType = 'keydown';
	this.keys = {
		left: 37,
		right: 39,
		up: 38
	};
	this.key = 'right';

	this.event.initEvent(this.eventType, true, true);
};

Runner.prototype.run = function() {
	this.key = (this.key === 'right') ? 'left' : 'right';
	this.action();
};

Runner.prototype.jump = function() {
	this.key = 'up';
	this.action();
};

Runner.prototype.action = function() {
	this.event.keyCode = this.keys[this.key];
	this.canvas.dispatchEvent(this.event);
};

var runner = new Runner();

setInterval(function() {
	runner.run();
}, 0);