title: Escape sequence for a space character in PHP
body: <p>Currently I'm using the below snippet, which indent the resulting HTML by using several space characters:</p>
  
  <pre><code>add_filter('get_search_form', 'filter_search_form');
  
  function filter_search_form($form) {
      $form = '      &lt;form role="search" method="get" id="searchform" action="' . home_url('/') . '"&gt;&lt;input type="text" placeholder="' . __('Search') . '" value="' . get_search_query() . '" name="s" id="s"&gt;&lt;input type="submit" id="searchsubmit" value="' . esc_attr__('Search') . '"&gt;&lt;/form&gt;' . "\n";
      return $form;
  }
  </code></pre>
  
  <p>Now I've been reading some about whitespace characters (<code>\t</code> for tab, <code>\n</code> for newline, etc.), but I'm not entirely sure how to implement this in this situation.
  I've tried using <code>\s</code> for a single space, but without any luck thusfar.</p>
  
  <p>Being relatively new to PHP, I hope you could assist (preferably without using a 'regular' space character).</p>