title: Q: load new PHP variables values without refresh
body: <p>I have wonder how to load or refresh PHP variables after assigning them example:</p>
  <pre><code>&lt;?PHP 
  if(isset($_POST['rnd])){$post = $_POST['rnd'];}
  ?&gt;
  
  &lt;input name='rnd' value='hey'&gt; //insert any value
  &lt;?PHP if(isset($post)){?&gt;
  &lt;div&gt;&lt;h1&gt;&lt;?PHP echo $post ?&gt;&lt;/h1&gt;&lt;/div&gt;&lt;?PHP }?&gt;
  </code></pre>
  <p>but if I do that I have to refresh the page to load the new value,
  so what I'm looking for how to load the new value without refresh the page,
  I searched the entire internet and did not find a helpful result,
  no matter what is the language,
  so anything will be helpful.</p>