Fixed XSS attack with err param.

frontend/App.vue

@@ -77,7 +77,11 @@
 			lofig.get('serverDomain', res => {
 				_this.serverDomain = res;
 			});
-			if (_this.$route.query.err) Toast.methods.addToast(_this.$route.query.err, 20000);
+			if (_this.$route.query.err) {
+				let err = _this.$route.query.err;
+				err = err.replace(new RegExp('<', 'g'), '&lt;').replace(new RegExp('>', 'g'), '&gt;');
+				Toast.methods.addToast(err, 20000);
+			}
 		},
 		events: {
 			'register': function () {