fix preview filed after ad_banner created.

app/assets/javascripts/inc/modal-preview.js

@@ -55,7 +55,7 @@ $(document).ready(function() {
  //          }
  //    })
 
-	$("a.preview_trigger").click(function(){
+	$("a.preview_trigger").live('click',function(){
 		$("#main-wrap").after("<span id='show_preview'></span>");
 		$.ajax({
 			type: 'PUT',