function setUpHeartBeat(ajaxURL, alternateURL) {
	
	var randomnumber = Math.floor(Math.random()*1001);
	var url=ajaxURL+ "&time="+randomnumber;
	keepAlive(url);
	window.setTimeout("setUpHeartBeat('"+ajaxURL+"','"+alternateURL+"')",1200000);
}

function keepAlive(url) {
	var script_id = null;
	var script = document.createElement('script');
	script.setAttribute('type', 'text/javascript');
	script.setAttribute('src', url);
	script.setAttribute('id', 'script_id');

	script_id = document.getElementById('script_id');
	if(script_id){
		document.getElementsByTagName('head')[0].removeChild(script_id);
	}

	// Insert <script> into DOM
	document.getElementsByTagName('head')[0].appendChild(script);
}