https://ecsdcards.com/common/plugins/RadEditorAjax/Resource/Resource.js

1//this is a sample code. Jeong Kyu Eum
2//tool handler function
3Telerik.Web.UI.Editor.CommandList["Resource"] = 
4//function name is not needed.
5function(commandName,editor,oTool)
6{
7    // RadEditor old version using editor.ShowDialog function
8    // RadEditor Ajax version using editor.showExternalDialog function
9    editor.ShowDialog(
10        "/common/plugins/RadEditorAjax/Resource/ResourceLibRadAjax.aspx",null,
11        //dimension
12        800,600, 
13        //function that is executed when the dialog is closed with the return value.
14        //see Default.aspx file 
15        function(returnValue)
16        {
17            if(returnValue)
18            {
19                editor.PasteHtml(returnValue);
20            }
21        },
22        null,'');
23};