Use the format:
http://yoursite/yourlist/newform.aspx?source=http://yoursite/yourlibrary/thankyou.aspx
Use the format:
http://yoursite/yourlist/newform.aspx?source=http://yoursite/yourlibrary/thankyou.aspx
Joomla automatically puts meta tag generator with comments about joomla in the site. here is how to remove tht