function isValidEmail(email, required) {
    if (required==undefined) {   // if not specified, assume it's required
        required=true;
    }
    if (email==null) {
        if (required) {
            return false;
        }
        return true;
    }
    if (email.length==0) {  
        if (required) {
            return false;
        }
        return true;
    }
    if (! allValidChars(email)) {  // check to make sure all characters are valid
        return false;
    }
    if (email.indexOf("@") < 1) { //  must contain @, and it must not be the first character
        return false;
    } else if (email.lastIndexOf(".") <= email.indexOf("@")) {  // last dot must be after the @
        return false;
    } else if (email.indexOf("@") == email.length) {  // @ must not be the last character
        return false;
    }
	
    return true;
}

function allValidChars(email) {
  var parsed = true;
  var validchars = "abcdefghijklmnopqrstuvwxyz0123456789@.-_";
  for (var i=0; i < email.length; i++) {
    var letter = email.charAt(i).toLowerCase();
    if (validchars.indexOf(letter) != -1)
      continue;
    parsed = false;
    break;
  }
  return parsed;
}

function checkFields() {
	if (document.contact_ppr_publicity.name.value == '' || document.contact_ppr_publicity.email.value == '' || document.contact_ppr_publicity.telephoneNumber.value == '' || document.contact_ppr_publicity.natureOfEnquiry.value == '' || document.contact_ppr_publicity.message.value == '') {
		alert("Please ensure the following are filled in:\n\n  - Name\n  - Email Address\n  - Telephone Number\n  - Nature Of Enquiry\n  - Message\n");
		return false;
	}else{
		if (! isValidEmail(document.contact_ppr_publicity.email.value)) {
        	alert("Please enter a valid email address");
        	return false;
    	}else{
			return true;
		}
	}
}