Java script errrrror in rails

Rails
1

when i click a button called add it should show a javascript form
showing an upload feature.its not displaying anything.instead of
tht its only showing the mwssage lik tis in console. please providee
a solution

ActionView::TemplateError (Called id for nil, which would mistakenly be
4 – if you really wanted the id of nil, use object_id) on line #1 of
app/views/lists/import.js.rjs:
1: id = dom_id(@list)

2

ActionView::TemplateError (Called id for nil, which would mistakenly be
4 – if you really wanted the id of nil, use object_id) on line #1 of
app/views/lists/import.js.rjs:
1: id = dom_id(@list)

Will need to see some code - however the simple answer from your error
is that @list is nil. Perhaps you are missing a:

@list = List.find(params[:id])

before this line 1?

Kind Regards
Luke