function validateVerifyExistingForm(){
		
		// quickie references to my fields
		var IDNo = document.getElementById('IDNo');
		var Surname = document.getElementById('Surname');
		var PhoneNo = document.getElementById('PhoneNo');
		var CCNo = document.getElementById('CCNo');
			
		// check the inputs  (main function nav)

	if(idField(IDNo, "mand", "subscriber number.")){
		if(alphaField(Surname, "opt", "surname.")){
			if(fourField(PhoneNo, "opt", "last four digits of your phone number.")){
				if(fourField(CCNo, "opt", "last four digits of your credit card.")){
					if(groupField()) {
						return true;
					}
				}
			}
		}
	}
	return false;
	}
	
	// function for checking our subscriber id field. we allow just numbers
	function idField(element, which, fieldDesc) {
		var NumExp = /^[0-9]+$/;
		if ((which == 'mand') && (element.value.length < 1)) {
			var shortStub = 'Please enter your ';
			alert(shortStub + fieldDesc);
			element.focus(); // set the focus to this input
			return false;
		} else if ((element.value.length > 1) && (!element.value.match(NumExp))) {
		var wrongStub = 'Please enter only numbers for the ';
			alert(wrongStub + fieldDesc);
			element.focus();
			return false;
		}else {
			return true;
		}
	}
	
	// function for checking surname field, allow only characters
	function alphaField(element, which, fieldDesc) {
		var alphaExp = /^[-a-zA-Z ']+$/;
		if ((which == 'mand') && (element.value.length < 2)) {
			var shortStub = 'Please enter your ';
			alert(shortStub + fieldDesc);
			element.focus(); // set the focus to this input
			return false;
		} else if ((element.value.length > 0) && (!element.value.match(alphaExp))) {
		var wrongStub = 'Please enter only letters for your ';
			alert(wrongStub + fieldDesc);
			element.focus();
			return false;
		}else {
			return true;
		}
	}
	
	// function for checking our 4 digit fields. we allow just numbers
	function fourField(element, which, fieldDesc) {
		var NumExp = /^[0-9]+$/;
		if ((which == 'mand') && (element.value.length != 4)) {
			var shortStub = 'Please enter the ';
			alert(shortStub + fieldDesc);
			element.focus(); // set the focus to this input
			return false;
		} else if ((element.value.length > 1) && (!element.value.match(NumExp))) {
		var wrongStub = 'Please enter only numbers for the ';
			alert(wrongStub + fieldDesc);
			element.focus();
			return false;
		}else {
			return true;
		}
	}
	
	// function for checking that at least one of phone no or cc no are entered.  
	
	function groupField(){
		var Surname = document.getElementById('Surname');
		var PhoneNo = document.getElementById('PhoneNo');
		var CCNo = document.getElementById('CCNo');
		if ((Surname.value == '') && (PhoneNo.value == '') && (CCNo.value == '')) {
			alert("Please enter either your surname or the last 4 digits of your phone or credit card number. ");
			Surname.focus();
			return false;
		} else {
			return true;
		}
	}