proper handling of failed sanity check in parse_counters + weird getAttribute workaround

backend.php

@@ -53,6 +53,8 @@
 		pg_query("set client_encoding = 'utf-8'");
 	}
 
+	if (!sanity_check($link)) { return; }
+
 	$fetch = $_GET["fetch"];
 
 	setcookie("ttrss_icons_url", ICONS_URL);
@@ -717,18 +719,7 @@
 		}
 
 		if ($subop == "sanityCheck") {
-
-			$error_code = 0;
-
-			$result = db_query($link, "SELECT schema_version FROM ttrss_version");
-
-			$schema_version = db_fetch_result($result, 0, "schema_version");
-
-			if ($schema_version != SCHEMA_VERSION) {
-				$error_code = 5;
-			}
-
-			print "<error error-code='$error_code'/>";
+			sanity_check();
 		}
 
 		if ($subop == "globalPurge") {

functions.js

@@ -358,6 +358,11 @@ if (!xmlhttp_rpc && typeof XMLHttpRequest!='undefined') {
 function parse_counters(reply, f_document, title_obj) {
 	try {
 		for (var l = 0; l < reply.childNodes.length; l++) {
+			if (!reply.childNodes[l] || !reply.childNodes[l].getAttribute) {
+				// where did this come from?
+				continue;
+			}
+
 			var id = reply.childNodes[l].getAttribute("id");
 			var t = reply.childNodes[l].getAttribute("type");
 			var ctr = reply.childNodes[l].getAttribute("counter");

functions.php

@@ -859,4 +859,24 @@
 		else
 			return "even";
 	}
+
+	function sanity_check($link) {
+	
+		$error_code = 0;
+		$result = db_query($link, "SELECT schema_version FROM ttrss_version");
+		$schema_version = db_fetch_result($result, 0, "schema_version");
+
+		if ($schema_version != SCHEMA_VERSION) {
+			$error_code = 5;
+		}
+
+		print "<error error-code='$error_code'/>";
+
+		if ($error_code != 0) {
+			return false;
+		} else {
+			return true;
+		}
+	}
+
 ?>