The XHTML page includes a state variable that must be present when you submit it, or the page will be discarded. Otherwise, you can put JS in the page.

Does this mean , I cannot call authorize method to login into GLU using our own registration app instead of login.xhtml ?

Hi, SENTHILKUMAR. Your initial post seemed to be about customizing login page. Now you mention "your custom registration app", which seems to be a totally different subject. Please correct me if I'm wrong. You need to create another ticket then, explaining your setup and goals in more details. If you indeed have a custom registration application and want to push users into Gluu's LDAP server to be able to log in with those entries after that, your 2 choices are SCIM (recommended) and direct writting to LDAP. For SCIM you'll need to also learn about UMA. You don't need to customize login page just for that.