A potentially dangerous Request.QueryString value was detected from the client when sending html markup from jquery post call to asp.net page

I m making an ajax call using jQuery to an ASP.NET page which acts as my ajax server page to save the data which i am sending to it in the query string. In the ASP.NET page when i am trying to read the querystring i am getting this error:

jQuery Validation – Multiple submit buttons on one asp.net form, different validation groups?

I have an asp.net form with a login section and a register section. There are two submit buttons that correspond to the appropriate section, login or register. I am using jquery validation, however I cannot find a way to specify validation groups as I would with normal asp.net validation. When I click the register button, right now it is asking for the login fields to be filled in. Anyone have any thoughts on this? THANKS!