[jquery] jQuery - Detecting if a file has been selected in the file input

I'd suggest try the change event? test to see if it has a value if it does then you can continue with your code. jQuery has

.bind("change", function(){ ... });

Or

.change(function(){ ... }); 

which are equivalents.

http://api.jquery.com/change/

for a unique selector change your name attribute to id and then jQuery("#imafile") or a general jQuery('input[type="file"]') for all the file inputs