Save only changed and new elements in the list

[dirs]

Hi,
I have a long list in which I can add new elements and change existing elements and one save button to save all the changes. When I want to save the list I want that only new elements that are being added and the line with changed elements should be sent. Any suggestions how to do it???
Thanks!

[redhead]

keep a hidden field holding the orriginal elements, then do a comparison to find changes between that and the changed list, then only sent what is different.

[dirs]

thanks