Change appearance of search form I want to change the appearance of the Drupal 7 search form.  I used this code in my preprocess-html.inc file for my Omega subtheme.  It didn't work.  How do I assign html classes to divs within the Drupal 7 preprocess-html.inc file?

Here's what I put in that didn't work:

&lt;html&gt;
&lt;body&gt;
&lt;?php

function mythemename_form_search_block_form_alter(&amp;$variables) {
  // custom functionality here 

}

?&gt;
    &lt;div class="row"&gt;
        &lt;div class="col-md-3"&gt;
            &lt;div class="input-group"&gt;
            &lt;input type="text" class="form-control" placeholder="Search for..."&gt;
            &lt;span class="input-group-btn"&gt;
            &lt;button class="btn btn-default" type="button"&gt;Go!&lt;/button&gt;
            &lt;/span&gt;
            &lt;/div&gt;
        &lt;/div&gt;
    &lt;/div&gt;

&lt;/body&gt;
&lt;/html&gt;


To clarify, how do I add this bootstrap html code to the template file? I need to add these classes to the search form.
To design the search block form you can override the existing search-block-form.tpl.php in the theme's template folder. 

&lt;?php

$variables['form']['search_block_form']['#attributes']['placeholder'] = "Search for...";
$variables['form']['search_block_form']['#attributes']['class'] = "form-control";

?&gt;

&lt;div class="row"&gt;
  &lt;div class="col-md-3"&gt;
    &lt;div class="input-group"&gt;      
      &lt;span class="input-group-btn"&gt;
        &lt;?php if (empty($variables['form']['#block']-&gt;subject)): ?&gt;
          &lt;button class="btn btn-default" type="button"&gt;&lt;?php print t('Go!');?&gt;&lt;/button&gt;
        &lt;?php endif; ?&gt;
        &lt;?php print $search_form; ?&gt;
      &lt;/span&gt;
    &lt;/div&gt;
  &lt;/div&gt;
&lt;/div&gt;