var xmlhttp = false;

if(window.XMLHttpRequest) {
	xmlhttp = new XMLHttpRequest();
} else if (window.ActiveXObject) {
	xmlhttp = new ActiveXObject("Microsoft.XMLHTTP");
} else if (window.createRequest) {
	xmlhttp = window.createRequest();
}

function makeHeadRequest(url) {
	if(xmlhttp) {
		xmlhttp.open("HEAD", url, true);
		xmlhttp.send(null);
	}
}

function logClick(logString) {
	makeHeadRequest("external.php?" + logString);
}