By default the portal sorting option is available in the "Portal setup" Dialog box. It's working fine.

But i need to write the script for the sorting the portal fields.

When I'm click the field name in first time record will be ascending and second time the record will be descending.

Can any one pls help to solve this issue..

Thanks for your time to read this..

See this thread. Link

that's fine, but how can i add a new record with this portal.

You didn't ask about adding child records, you asked about sorting portals.

yes, but Is any possibility to fit my requirement ?

What exactly are you asking? How to create a child record? You can just turn on Allow Create by editing the relationship btw the parent and child.

Please provide more detail in your question if you want more detail in your answers.