//添加好友
function addfriend(username,nickname){
	makeAddFriendRequest("/ajax/addfriend.php?username="+username+"&nickname="+nickname);
}

function makeAddFriendRequest(url){
	http_request = false;
	//支持XMlHttpRequest类的浏览器，如mozilla
	if (window.XMLHttpRequest) { // Mozilla, Safari,...		
		http_request = new XMLHttpRequest();
		if (http_request.overrideMimeType) {
			http_request.overrideMimeType('text/xml');
		}
	} else if (window.ActiveXObject) { // IE
	
		try {
			http_request = new ActiveXObject("Msxml2.XMLHTTP");
		} catch (e) {
			try {
				http_request = new ActiveXObject("Microsoft.XMLHTTP");
			} catch (e) {}
		}
	}		

	if (!http_request) {
		alert('sorryplease update your ie!');
		return false;
	}
			

	http_request.open('GET', url, true);
	http_request.onreadystatechange =function(){
		if (http_request.readyState == 4 ){
			if( http_request.status == 200){				
				flag = http_request.responseText;
				if(parseInt(flag) == -4){
					alert('Please login!');
				}else if(parseInt(flag) > 0){
					alert('add sucessfully!');
				}else if(parseInt(flag) == -3){
					alert('already added!');
				}else{
					alert('add false!');
				}
			}
		}
	}
	http_request.send(null);
}