Hiding form fields doesn't really help improve security. However to create a hidden field, simply use the hidden type attribute:
<input type="hidden" ... />
blocblue
Practically a Posting Shark
837 posts since Jan 2008
Reputation Points: 272
Solved Threads: 161
Skill Endorsements: 12
If you want to secure the form field values during the transmission from the browser to the server you can use HTTPS.
broj1
Nearly a Posting Virtuoso
1,211 posts since Jan 2011
Reputation Points: 167
Solved Threads: 164
Skill Endorsements: 13