How to show a button right after a file (publicThumbNailPath) is chosen?

Hi guys The PublicThumbNailPath (PTNP) of an System.FileDocument object becomes filled in after selecting a file through a standard imageUploader functionality. Now I am wondering how to show a button right after a file is chosen (conditionally visible) and the publichThumbNailPath is filled in ? Here is one thought of me and further I am wondering what you could advice... 1 - Is it possible to base a button visibility on the filled PTNP?
1 answers

Maybe you can use a onchange handler on the PTNP field? Something like:

$('.PTNP label').change(function() { $('.myButton').show(); })

Add classes to your PTNP (in this example class = PTNP) and your button (in this example myButton). Set initial button style to: display: none;

I tried it out, however in my test the PTNP was not filled when uploading a file..