the user agent chooses its own default style, and there is (to my knowledge) no CSS attributes you can change to determine the masking character.
Of course, this is possible if the password field is...

the javascript calls the php script on the server and writes the returned html into the same div p or other tag that the original was written
The JQuery library has good instructions and basic...

http://devphp.sourceforge.net/
using the portable version on a thumbdrive in customer offices
the full version on my pc

search = '<form action="http://www.ututorial.net/search" id="cse-search-box"><div><input type="hidden" name="cx" value="partner-pub-3996237323979957:tenb6ft9bbh" /><input type="hidden" name="cof"...