diff --git a/dev/install/config-form.html b/dev/install/config-form.html
index b0ebe3a05..886f9fdb3 100644
--- a/dev/install/config-form.html
+++ b/dev/install/config-form.html
@@ -316,13 +316,12 @@ foreach($locales as $code => $details) {
 		<script type="text/javascript">
 			var children = $('database_selection').childNodes;
 			var disabledAdapterClick = function(e) {
-				if (!e) e = window.event;
 				// Hide all existing warnings
 				var elements = getElementsByClassName('databaseError');
 				for(var i = 0; i < elements.length; i++) elements[i].style.display = 'none';
-				if (e.target.parentNode.childNodes[0].getAttribute('notavailable')) {
+				if (this.parentNode.childNodes[0].getAttribute('notavailable')) {
 					// Show the warning for this adapter
-					getElementsByClassName('databaseError', e.target.parentNode)[0].style.display = 'block';
+					getElementsByClassName('databaseError', this.parentNode)[0].style.display = 'block';
 					return false;
 				}
 			}