diff --git a/chrome/content/zotero/xpcom/utilities.js b/chrome/content/zotero/xpcom/utilities.js
index cf4468c1b..7f3200c6e 100644
--- a/chrome/content/zotero/xpcom/utilities.js
+++ b/chrome/content/zotero/xpcom/utilities.js
@@ -156,8 +156,16 @@ Zotero.Utilities.prototype.cleanTags = function(x) {
  *  <ZOTEROHELLIP/> => &hellip;
  */
 Zotero.Utilities.prototype.htmlSpecialChars = function(str) {
-	if (typeof str != 'string') {
-		throw "Argument '" + str + "' must be a string in Zotero.Utilities.htmlSpecialChars()";
+	switch (typeof str) {
+		case 'string':
+			break;
+		
+		case 'number':
+			str = str + '';
+			break;
+		
+		default:
+			throw "Argument '" + str + "' must be a string in Zotero.Utilities.htmlSpecialChars()";
 	}
 	
 	if (!str) {