diff --git a/attract/static/js/tasks.js b/attract/static/js/tasks.js
index 301df07..44b4be8 100644
--- a/attract/static/js/tasks.js
+++ b/attract/static/js/tasks.js
@@ -41,7 +41,7 @@ function task_open(task_id) {
 
     var project_url = ProjectUtils.projectUrl();
     if (typeof project_url === 'undefined') {
-        throw "ProjectUtils.projectUrl() undefined";
+        throw new ReferenceError("ProjectUtils.projectUrl() undefined");
     }
 
     $('#col_right .col_header span.header_text').text('Task details');
@@ -72,7 +72,7 @@ function shot_open(shot_id) {
 
     var project_url = ProjectUtils.projectUrl();
     if (typeof project_url === 'undefined') {
-        throw "ProjectUtils.projectUrl() undefined";
+        throw new ReferenceError("ProjectUtils.projectUrl() undefined");
     }
 
     $('#col_right .col_header span.header_text').text('Shot details');