var keepalive = {
	lifetime: 300,
	root_uri: 'http://www.youcontent.nl/',
	xmlHttp: new xmlHttp(),

	trigger: function()
	{
		this.xmlHttp.open('HEAD', this.root_uri);
		this.xmlHttp.send(null);
	},

	keepalive: function()
	{
		var limit = 1000 * Math.max(60, this.lifetime - 30);
		window.setTimeout(function(){try{keepalive.trigger();}catch(e){};keepalive.keepalive()}, limit);
	}
};
keepalive.keepalive();