SharePoint 2010 FBA : Redirect to forms login page by skipping windows/forms dropdown sign in page

go to webapplication web.config file find below tag

<authentication mode="Forms">

      <forms loginUrl="/_login/default.aspx" />

</authentication>

replace with below code

<authentication mode="Forms">

      <forms loginUrl="/_forms/default.aspx" />

</authentication>

save it. when you hit your url it will redirect to forms login page instead of dropdown sing in page.