how do i use a ruby if statement in a js.erb file?

Question

I need to do something like shown below; add a jquery effect depending on the value of an instance object in rails

("$('#cart').show(2000);") if @cart.total_items ==1

Answer 1

<% if @cart.total_items ==1 %>
  $('#cart').show(2000);
<% end %>

Answer 2

@xdazz answer is right , but i used to use the conditional statements as follows

var mycount = <%= @cart.total_items %>

if (mycount == 1){
$("#cart").show(2000)
}

The reason i use mostly conditional statements in javascript (in js.erb file) is because this seems easy to handle