You clicked ribbon buttons a lot in SharePoint 2010. Sometimes, you as developer are interested in what code is executed when particular button is clicked. I’m going to show how you can easily find particular js handler for any ribbon button. For example, imagine you want to find what code is fires when you click “Edit HTML Source” drop down button in a rich text editor. First of all inspect this element using firebug, or any favorite browser’s dev tool.
Consider id attribute, for example Ribbon.EditingTools.CPEditTab.Markup.Html.Menu.Html.EditSource-Menu16. Next go to 14 hive and under TEMPLATE\GLOBAL\XML\ find cmdui.xml file. This file contains definition for all ribbon buttons in SharePoint. Search in this file by word Ribbon.EditingTools.CPEditTab.Markup.Html.Menu.Html.EditSource, you’ll find this definition.
This is definition for our button, and we are interested in Command attribute, which is equals to EditSource.
as you can see from screenshot above, breakpoint fire, $p0 parameter equals to “EditSource”, as expected. Next you can step into to find exact code, that will be fire:
this is RTE.RichTextEditor.editSource(). We found our handler! You can use this approach to find any other ribbon handlers, sometimes steps may differ, but I was trying to show common technique.
Hope this helps and good luck in spdevelopment!