function request(callback) {
		var xhr = getXMLHttpRequest();
		
		xhr.onreadystatechange = function() {
			if (xhr.readyState == 4 && (xhr.status == 200 || xhr.status == 0)) {
				callback(xhr.responseText);
				document.getElementById("loader").style.display = "none";
			} else if (xhr.readyState < 4) {
				document.getElementById("loader").style.display = "block";
			}

		};
	
		var url = encodeURIComponent(document.getElementById("url").value);
		
		xhr.open("GET", "ajax/seo.php?url=" + url, true);
		xhr.send(null);
		return false;
	}
	
	function readData(sData) {
		document.getElementById("seo_req").innerHTML = sData;
	}