function checkform ( form )
{  
  // ** START **
  if (form.name.value == "") {
    alert( "Please enter your name." );
    form.name.focus();
    return false ;
  }
  // ** END **
  
  // ** START **
  if (form.email.value == "") {
    alert( "Please enter your email." );
    form.email.focus();
    return false ;
  }
  // ** END **  

  // ** START **
  if (form.company.value == "") {
    alert( "Please enter your company's name." );
    form.company.focus();
    return false ;
  }
  // ** END **     
  
    // ** START **
  if (form.phone.value == "") {
    alert( "Please enter your phone number." );
    form.phone.focus();
    return false ;
  }
  // ** END **   
  return true ;
}