Hi,
You will need to do it the other way around:
1. Customize the AJAXUploader's LayoutTemplate to remove the default upload button;
2. Use your own Upload button and handle onclick for that button with JavaScript;
3. Inside your event handler, performs whatever validation you wish to perform;
4. If the validation passes, you would call the AJAXUploader's upload method to start the upload. If the validation fails, then you do not call upload. The code will be something like this:
Code: JavaScript
function your_click_handler()
{
//Perform your validation logic
if (validate_your_drop_down())
{
//Get the uploader object
var uploader = eo_GetObject("AJAXUploader1");
//Start the upload
uploader.upload();
}
}
Hope this helps.
Thanks!