title: Illegal nesting: nesting within plain text is illegal
body: <p>I'm new to HAML and I have an error: <code>Illegal nesting: nesting within plain text is illegal.</code>. Currently, I'm trying to change my erb to haml but it is not working. Here is my erb. </p>
  
  <pre><code>&lt;script src="https://js.braintreegateway.com/v2/braintree.js"&gt;&lt;/script&gt;
  &lt;h2 class="mbs"&gt;New Subscription
  &lt;/h2&gt;
  &lt;%= simple_form_for :subscription, :url =&gt; subscribe_subscription_path(@plan.id), :id =&gt; "checkout-form" do |f| %&gt;
    &lt;% if current_user and !current_user.has_payment_info? %&gt;
      &lt;%= render 'customer_form'%&gt;
    &lt;% end %&gt;
    &lt;br/&gt;
    &lt;p&gt; Please enter payment details: &lt;/p&gt;
    &lt;div id="payment-form"&gt;&lt;/div&gt;
    &lt;div id="coinbase-container-id"&gt;&lt;/div&gt;
    &lt;div class="form-actions"&gt;
      &lt;%= f.submit t(:subscribe), :class =&gt; 'btn btn-primary' %&gt;
    &lt;/div&gt;
    &lt;script charset="utf-8" type="text/javascript"&gt;
      var clientToken = "&lt;%= @client_token %&gt;";
      braintree.setup(clientToken, "dropin", {
        container: "payment-form",
        coinbase: { container: "coinbase-container-id" }
        });
    &lt;/script&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>My HAML is: </p>
  
  <pre><code>%script{:src =&gt; "https://js.braintreegateway.com/v2/braintree.js"}
  %h2.mbs
  New Subscription
  = simple_form_for :subscription, :url =&gt; subscribe_subscription_path(@plan.id), :id =&gt; "checkout-form" do |f|
    - if current_user and !current_user.has_payment_info?
      = render 'customer_form'
    %br/
    %p Please enter payment details:
    #payment-form
    #coinbase-container-id
    .form-actions
      = f.submit t(:subscribe), :class =&gt; 'btn btn-primary'
    %script{:charset =&gt; "utf-8", :type =&gt; "text/javascript"}
      var clientToken = "#{@client_token}";
      braintree.setup(clientToken, "dropin", {
        container: "payment-form",
        coinbase: { container: "coinbase-container-id" }
      });
  </code></pre>
  
  <p>What is wrong? Why is that error showing?</p>