diff --git a/app/assets/javascripts/users_select.js b/app/assets/javascripts/users_select.js
index 6aa0e1cd2b61bbbf00dc4e69485425545197694e..3020b7cc2392e9e0dd383e30338256cd5ddffd61 100644
--- a/app/assets/javascripts/users_select.js
+++ b/app/assets/javascripts/users_select.js
@@ -325,6 +325,10 @@
     };
 
     UsersSelect.prototype.user = function(user_id, callback) {
+      if(!/^\d+$/.test(user_id)) {
+        return false;
+      }
+
       var url;
       url = this.buildUrl(this.userPath);
       url = url.replace(':id', user_id);