title: Submit button clicking changing the value of it to another thing
body: <p>maybe very easy!
  I'm php coder and I don't have experience in js but I must do this for one of my codes 
  suppose I have sub1 in page after clicking it must be that sub1 but value now is sub2</p>
  
  <pre><code>       &lt;html&gt;
          &lt;head&gt;
          &lt;title&gt;pharmacy&lt;/title&gt;
          &lt;/head&gt;
          &lt;body&gt;
          &lt;form method="post" action="pharmacy.php"&gt;
          &lt;?php
         //some code
              if(array_key_exists('update',$_POST)){
                  //somecode
                  }
          ?&gt;
  &lt;input type="submit" name="update" value="&lt;?php echo if(isset($_GET['update'])) ? 'Show' : 'Update' ?&gt; "&gt;
      &lt;/form&gt;
      &lt;/body&gt;
      &lt;/html&gt;
  </code></pre>