Developer's manual

This is the complete Developer's manual for Ultimate Dropdown Menu Version 4.6. If you're using the menu for the first time I recommend reading the Quick start guide first.

You can also download the developer's manual in various different formats.

A note about tabbed code-examples

UDM is available in a choice of configuration languages, so many of the code examples have to show the same options in more than one syntax. To accomodate this I've come up with tabbed code blocks:

Two white layers partially overlaid, each of which show part of a code example in a different language - javascript underneath and PHP above. Each layer has a tab at the top which says 'JS' or 'PHP' respectively

You can view each language by clicking the relevant tab at the top of each block.


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Recent articles

Initialization trigger element
Defining a trigger element allows the menu script to initialize before window.onload!
The implications of initializing before window.onload
Any scripting you do which is tied into the API "Ready" event (event "010") may need to be checked to make sure it still behaves correctly.
Setting the character-match value for allowed filenames
The file path in the PHP configuration can now contain "\" (backslash) and ":" (colon), for greater compatibility with Windows server paths.
Refreshing the tree after dynamic changes
Using the um.refresh method, you can add or remove items after page load, or populate the menus using AJAX.

Looking for UDM 3?

Documentation for UDM 3 is at


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UDM 4 is valid XHTML, and in our judgement, meets the criteria for WAI Triple-A conformance.