I want to check two values are equal or not and send error message
accordingly.
I am using form_for tag of foreman rails.
and that form_tag contains two select statement.
Could you please provide any example to do so.
I assume you are using rails select helper inside the form_tag? Then you
can attach custom js function in its html_options:
http://apidock.com/rails/ActionView/Helpers/FormOptionsHelper/select
Something like :onchange => 'myFunc()' should work. In your js function you
check if both selects are non-blank and have the same value. At least that
is how I would go about it.