function chkForm(frm) {
  // the name of the form
  f = frm;

  // change msg to the name of any field you want to make required.
  if (f.first_name) {
    if (f.first_name.value == '') {
      alert('Please enter your first name.');
      return false;
    }
  }
if (f.last_name) {
    if (f.last_name.value == '') {
      alert('Please enter your last name.');
      return false;
    }
  }
if (f.address) {
    if (f.address.value == '') {
      alert('Please enter your address.');
      return false;
    }
  }
if (f.apt_name) {
    if (f.apt_name.value == '') {
      alert('Please enter the apartment name.');
      return false;
    }
  }  
if (f.apt_num) {
    if (f.apt_num.value == '') {
      alert('Please enter the apartment number.');
      return false;
    }
  }  
if (f.phone) {
    if (f.phone.value == '') {
      alert('Please enter a contact number.');   
      return false;
    }
  } 
if (f.pickup_date) {
    if (f.pickup_date.value == '') {
      alert('Please select a pickup date.');   
      return false;
    }
  }
if (f.email) {
    if (f.email.value == '') {
      alert('Please enter a valid email address, your confirmation will be sent there.');
      return false;
    }
  }   
}