var startPoll = function() {
		 $.post('<url>', {},onPollRequestComplete, 'json');

}

var onPollRequestComplete = function(response) {

		responseObject = eval(response);

		if(responseObject.success) {
			//Do something with the response
		}

		setTimeout(startPoll,5000); //Make next polling request after 5 seconds

}

startPoll();