https://www.dsfm.mb.ca/common/plugins/RadEditorAjax/CustomTool/CustomTool.js

1//this is a sample code. Jeong Kyu Eum
2//tool handler function
3Telerik.Web.UI.Editor.CommandList["CustomTool"] = 
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/CustomTool/DefaultAjax.aspx",null,470,500, 
11        //function that is executed when the dialog is closed with the return value.
12        //see Default.aspx file 
13        function(returnValue)
14        {
15            if(returnValue)
16            {
17                editor.PasteHtml(returnValue);
18            }
19        },
20        null,'');
21};