This plugin takes code that looks like this:
<select class="multitier" name="my_select">
<option value="">(none)</option>
<option value="1">Category 1</option>
<option value="2">Category 1 > Subcategory 1</option>
<option value="3">Category 1 > Subcategory 2</option>
<option value="4">Category 2</option>
<option value="5">Category 2 > Subcategory 1</option>
<option value="6">Category 2 > Subcategory 2</option>
<option value="7">Category 2 > Subcategory 3</option>
<option value="8">Category 2 > Subcategory 4</option>
<option value="9">Category 2 > Subcategory 4 > Subsubcategory 1</option>
<option value="10">Category 2 > Subcategory 4 > Subsubcategory 2</option>
</select>
... and transforms it into a select box that just shows (none), Category 1, and Category 2. Then when you click on Category 1, a new select box pops up showing Subcategory 1 and Subcategory 2.
There is no configuration. Just give your select tag a class="multitier" and you are good to go.
Note: after releasing this, I then found this project, which seems to be a much more complete version of what I was trying to do:
http://code.google.com/p/jquery-option-tree/
With that said, I still think mine's pretty simple and cool.
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