Q1627 How can I ensure that all the buttons on are form are all clicked before allow the submit button to submit the form?

<script language="JavaScript"><!--
function validate(form) {
  for (var i=0; i <form.elements.length; i++) {
    if (form.elements[i].type == 'button') {
      if (!form.elements[i].clicked) {
        alert('Click all the buttons first!');
        return false;
      }
    }
  }
  return true;
}
//--></script>

<form onSubmit="return validate(this)">
<input type="button" value="button" onClick="this.clicked=true">
<input type="button" value="button" onClick="this.clicked=true">
<input type="button" value="button" onClick="this.clicked=true">
<input type="button" value="button" onClick="this.clicked=true">
<input type="submit">
</form>