regular expression for mask in validation.xml

hi all,
Can anybody please tell me how do we use a regular expression to validate when a field starts with any of the given strings say "abc","xyz","ghi"
i have tried this in validation.xml
<var-name>mask</var-name>
<var-value>^[^(abc)|(xyz)|(ghi)]]</var-value>
but this did not work

Not sure about how to use it in Struts, but this regexp seems better:

^(abc|xyz|ghi)

As an aside, "this did not work" is a rather deficient description of a problem. How did it not work - was the validation used, but the regexp didn't capture what you thought it would capture? Or was the validation never used? Or something else?
[ February 22, 2006: Message edited by: Ulf Dittmer ]

thanks Ulf Dittmer ,

with did not work i meant that the validation did not work as expected i mean its checking for string that starts with any of the letters or combination of letters in the list ie a b c x y z g h i seperately,sorry for not making it clear earlier. i have tried with the regular expression which u have suggested but this doesnot work as expected as well

this does not work as expected as well

Please, read this before your next post.

Both this and this regexp tester indicate that the regexp I gave matches "abc...", but not "a...", and it uses only standard regexp features.