JavaScript: Designer - Custom Open Dialog

JS:

designer.jsObject.ActionOpenReport = function () {
 alert("Open event!");
 //write your code here
 };

Web, NET Core:

<script>
 //where jsStiWebDesigner1 - "js" + Designer ID
 jsStiWebDesigner1.onready = function () {
 jsStiWebDesigner1.ActionOpenReport = function () {
 alert("Open event!");
 //write your code here
 };
 }
 </script>