Is the following possible on a ASP page.

I have a form field (frmMidName) and would like to call some javascript via onBlur on this formfield.
I want the javascript to check what ever is entered in the form field and if this is equal to a set variable (e.g. Charles) I would like to populate a hidden field. The asp page that my 1st page posts to populates a database based on the form fields, thus if Charles is entered in frmMidName then the database get populated with what ever is in this hidden field.

I know how to do this by reloading the 1st ASP page however a number different pages all post to this page so reloading is not an option, thus can the onBlur populate a hidden field on the fly.

Thanks in advance
David