main: move to async infobox calls

tt-rss.js

@@ -645,6 +645,7 @@ function userSwitch() {
 }
 
 function editFeedDlg(feed) {
+	try {
 
 		disableHotkeys();
 	
@@ -658,21 +659,21 @@ function editFeedDlg(feed) {
 			return;
 		}
 	
-	if (xmlhttp_ready(xmlhttp)) {
+		var query = "";
 	
 		if (feed > 0) {
-			xmlhttp.open("GET", "backend.php?op=pref-feeds&subop=editfeed&id=" +
-				param_escape(feed), true);
-			xmlhttp.onreadystatechange=infobox_callback;
-			xmlhttp.send(null);
+			query = "backend.php?op=pref-feeds&subop=editfeed&id=" +	param_escape(feed);
 		} else {
-			xmlhttp.open("GET", "backend.php?op=pref-labels&subop=edit&id=" +
-				param_escape(-feed-11), true);
-			xmlhttp.onreadystatechange=infobox_callback;
-			xmlhttp.send(null);
+			query = "backend.php?op=pref-labels&subop=edit&id=" +	param_escape(-feed-11);
 		}
-	} else {
-		printLockingError();
+	
+		new Ajax.Request(query, {
+			onComplete: function(transport) { 
+				infobox_callback2(transport); 
+			} });
+
+	} catch (e) {
+		exception_error("editFeedDlg", e);
 	}
 }