action url with anchor - ( not a js guru)

in my user_helper.rb    def registration_form       content_for(:ready) do         "window.location = window.location.href + '#register_form';"       end    end

in my new.html.haml view - registration_form

first pass (correct) http://localhost:3000/en_GB/signup#register_form

subsequent pass ( incorrect .. but normal as per the js code) http://localhost:3000/en_GB/signup#register_form%23register_form

how should I modify the js code to avoid repetition of the anchor, in Ruby I would write that ..

"... unless window.location.href already contains '#register_form' " " ..... window.location = window.location.href + '#register_form' " " ... end

but in .js is there any equivalent ?

thanks for your feedback

got the answer from js guru ..

use => window.location.href.indexOf('#register_form') == -1