Ajax check username available in rails

1. Client

 

<% = Link_to_remote ' Check Availability ',
: Submit =>   " Signupform " ,
: URL => {: Controller =>   ' Users ',: Action => 'check _ username_avaiable '},
: Update =>   ' Check_username ',
: HTML => {: Class =>   ' Smalltext'} %>

 

 

 

Note that the submit here is the form ID, and the update is the ID of the Dom to be updated after Ajax is returned.

2, Server

Def check_username_avaiable
Exist_user = User. find_by_username (Params [: username])
Exist_user =   ' Yes '   If Params [: username] =   ' Demo '
If Exist_user.nil ? Then
Render: Partial => ' Username_avaiable ' ,: Locals => {: Username => Params [: username]}
Else
Render: Partial => ' Username_not_avaiable ' ,: Locals => {: Username => Params [: username]}
End
End