Manually trigger 'open file dialog' using plupload

Question

I'm using plupload to client scaling of pictures before they are uploaded. I like the feature that it gracefully falls back to html4 if the user doesn't have flash, silverlight etc engines installed.

I want to be able to start the upload when the user clicks certain elements on the page and i want to handle the events (sometimes stopping a file dialog from opening). In fact i'd like to pop open the file dialog using javascript.

Ok, so HTML4 (or rather the browser, except chrome :P) won't let me do this, unless the user clicks a browse-button (or an overlay covering a browse-button), so when i get the fallback to HTML4 i'll accept that i can't do it, but most users will have flash or silverlight installed and they do not have this restriction. So my question is this:

How do i trigger the file open dialog in plupload (keeping in mind i only need the flash and silverlight engines to do this).

Answer 1

The former solutions not worked on iPhones with plupload 2.1.2.

The following code did the trick (jquery needed):

$("#id_of_the_second_button").click(function() { 
    $('div.moxie-shim input[type=file]').trigger('click');
});