diff --git a/wp-includes/js/tinymce/themes/advanced/jscripts/link.js b/wp-includes/js/tinymce/themes/advanced/jscripts/link.js
index 31b38782bd..74045bd5f6 100644
--- a/wp-includes/js/tinymce/themes/advanced/jscripts/link.js
+++ b/wp-includes/js/tinymce/themes/advanced/jscripts/link.js
@@ -25,7 +25,7 @@ function init() {
 			option.selected = true;
 	}
 
-	document.forms[0].href.value = tinyMCE.getWindowArg('href');
+	document.forms[0].href.value = tinyMCE.getWindowArg('href') || 'http://';
 	document.forms[0].linktitle.value = tinyMCE.getWindowArg('title');
 	document.forms[0].insert.value = tinyMCE.getLang('lang_' + tinyMCE.getWindowArg('action'), 'Insert', true);