poller

poller.js

function poller(callback, delay){
	var polling, timeout;
	function set(time){
		timeout = setTimeout(function(){
			// if a timeout is already scheduled in IE,
			// clearTimeout won't remove it from the schedule
			if(!polling || polling != time){ return; }
			callback();

			set(time);
		}, delay);
	}
	function start(){
		set(polling = +(new Date));
	}
	start();

	return {
		pause: function(){
			polling = 0;
			clearTimeout(timeout);
			timeout = null;
		},
		resume: function(){
			if(!polling){
				start();
			}
		}
	};
}