diff --git a/public/js/whiteboard.js b/public/js/whiteboard.js
index 947e242..8f595f2 100644
--- a/public/js/whiteboard.js
+++ b/public/js/whiteboard.js
@@ -33,6 +33,9 @@ var whiteboard =  {
 		for(var i in newSettings) {
 			this.settings[i] = newSettings[i];
 		}
+		this.settings["username"] = this.settings["username"].replace(/[^0-9a-z]/gi, '');
+		this.settings["whiteboardId"] = this.settings["whiteboardId"].replace(/[^0-9a-z]/gi, '');
+
 		var startCoords = [];
 		var svgLine = null;
 		var svgRect = null;