comparevalidator .net

[ynor]

i have 2 comparevalidator each on textbox. the valuetocompare is changing upon the context of the texbox. so it is not static value.i managed it by when submitting the page make the control of the validator by changing the valuetocompare and everything works good,but the problem is i don't want to submit to the server i need it on client side.
can anybody has the good idea of how it could be the script.
(i'm working vb and js)
thank you,;)