Question

In the following A and B should be equivalent but only version A works. The rails string evaluation seems broken or occurring too early/late or something. Any ideas?

<% content_for :main do %>

<script type="text/javascript">

  $(function(){

    //$("#users-new").dialog();          //A

    $(<%= "\"#users-new\"" %>).dialog();  //B

  });

</script>

<div  id="users-new">
  testing
</div>

<% end %>

Answer 1

Rails3+ HTML encodes the content in <%= ... %>by default. That means that your B comes out like this:

$("#users-new").dialog();

and that makes no sense in JavaScript. You want one of these:

$(<%= raw "\"#users-new\"" %>).dialog();
$(<%= "\"#users-new\"".html_safe %>).dialog();

Either of those will give you the JavaScript that you’re expecting:

$("#users-new").dialog();