Question : How to build small upload script from scratch with progress upload?

For ex. like on this page ?
Anybody has got working examples ?
Ajax-based, without reloading page.

Answer : How to build small upload script from scratch with progress upload?

These websites can help you:
http://www.ajaxf1.com/tutorial/ajax-file-upload-tutorial.html
http://www.anyexample.com/programming/php/php_ajax_example__asynchronous_file_upload.xml
http://www.noupe.com/javascript/most-wanted-ajax-techniques-50-ajax-examples-and-tutorials.html