title: Custom CSS classes for SQLFORM widget input in web2py
body: <p>Given this SQLFORM in the controller:</p>
  
  <pre><code>form = SQLFORM.factory(db.source_server, db.target_server)
  </code></pre>
  
  <p>with the following table definition:</p>
  
  <pre><code>db.define_table('target_server',
                  Field('target_url', 'string'),
                  Field('target_user', 'string'),
                  Field('target_password', 'password'))
  db.define_table('target_server',
                  Field('target_url', 'string'),
                  Field('target_user', 'string'),
                  Field('target_password', 'password'))
  </code></pre>
  
  <p><strong>how can I apply custom CSS classes for each form widget <code>&lt;input&gt;</code> element?</strong></p>
  
  <pre><code>  {{=form.custom.begin}}
    &lt;fieldset&gt;
      &lt;legend&gt;Source Server&lt;/legend&gt;
      &lt;div class="clearfix"&gt;
        &lt;label for="source_url"&gt;URL:&lt;/label&gt;
        &lt;div class="input"&gt;
  
          &lt;input class="bla bla" name="field_name"&gt;
  
        &lt;/div&gt;
      &lt;/div&gt;
    ...
    {{=form.custom.end}}
  </code></pre>