jQuery: Change element type from hidden to input
With jQuery 1.4 you can change the type of an input while it's detached.
marker = $('<span />').insertBefore('#myInput');
$('#myInput').detach().attr('type', 'text').insertAfter(marker);
marker.remove();
I'm not sure this is possible, so I would suggest using a hidden div to contain the input element, which can be shown as needed. The text input field can still hold data even if it's hidden.