how to check if a file is selected using javascript?

Question

In php this is how you would check if a file is selected:

$_FILES[\'item\'][\'size\']>0

what about in JavaScript?

I need to know

Answer 1

I use this javascript:

var file_selected = false;
function showNoFile() {
    if(!file_selected) { alert('No file selected!'); } // or anything else
}

with this html for the file button:

....

hope that helps!