title: Checking if form element exist
body: <p>I save the form elements to a file and the following is working as expected.</p>
  
  <pre><code>$t_str .= "viewMandatory=".$_GET['viewMandatory'] ."\n";
  </code></pre>
  
  <p>But what I need is that if $_GET is set only then it should be appended to "t_str" string. </p>
  
  <p>If no value for viewMandatory is received from the form, it should print nothing. How to add this check to the above statement?</p>