form charset not available in IE?

[YourNameHere]

I have a login form. the password field from the register form  is hashed sha1 before being inserted into the database.

Then to authenticate, I check whether or not the login password field matches the db copy. Very simple. However, it is my understanding that the accept-charset attribute of <form> will change the way something is hashed.

I found this out after seeing that the login hash is different from the register hash despite the correct password being typed and looking up why it would be different.

IE doesn't support the "accept-charset" attribute. So how would I make it the same hash/charset? Is there a workaround? Or is there another way that this could be occurring? Any guidance on this is gratefully appreciated as it has halted production.