Question

When a user selects a file, I want another file field to appear. It works for the first file, but if i choose a file in the second field, it doesn’t get called again. Why not?

jquery script

 $(document).ready(function() {
        var i = 1;

        $('input:file[name$=\'uploadedFile'+(i-1)+'\']').change(function() {
            var file = $(this).val();

            if(file !== null && file !== "") {
                $(this).after("<input type=\"file\" name=\"uploadededFile"+i+"\" />");
                i++;
            }
        });
    });

html form

<form action="PHP/file.php" method="post" enctype="multipart/form-data">
    <input type="hidden" name="MAX_FILE_SIZE" value="500000" />
    <input type="file" name="uploadedFile0" />
    <input type="submit" value="SUBMIT" />
</form>

Answer 1

When you write $(...).change(function), you are adding the handler to the elements that are currently in the jQuery object. When you add a new <input>, it doesn;t have any event handlers.

You need to call .live, which will handle the event for all matching elements, no matter when they were created.
For example:

$('input:file:last').live('change', function() { ... });

Note that the selector is only evaluated once, so it won’t pick up changes in i.
Instead, you should use :last.