function addComment(url,comment){
	var params = "comment="+comment;
	var http = new XMLHttpRequest();
	http.open("POST", url, true);
	http.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
	http.setRequestHeader("Content-length", params.length);
	http.setRequestHeader("Connection", "close");
	http.onreadystatechange = function() {
		if(http.readyState == 4 && http.status == 200) {
			alert(http.responseText);
		}
	}
}