function validate_radio(field,alerttxt) {
	myOption = -1;
	for (i=field.length-1; i > -1; i--) {
		if (field[i].checked) {
			myOption = i; i = -1;
		}
	}
	if (myOption == -1) {
		return alerttxt;
	} else {
		return "";
	}
}

function validate_required(field,alerttxt) {
	with (field) {
		if (value==null||value=="")
		  {focus();return alerttxt;}
		else {return ""}
	}
}

function validate_email(field,alerttxt) {
	with (field) {
		apos=value.indexOf("@")
		dotpos=value.lastIndexOf(".")
		if (apos<1||dotpos-apos<2) 
		  {focus();return alerttxt;}
		else {return ""}
	}
}

function validate_duplicatefield(field1,field2,alerttxt) {
	if (field1.value != field2.value) 
	  {field2.focus();return alerttxt;}
	else {return ""}
}

function validate_contact_form(thisform) {
	with (thisform) {
		var check = "";
		check += validate_required(txtFirstname,"First name is a required field\n");
		check += validate_required(txtSurname,"Surname is a required field\n");
		check += validate_required(txtAddressLine1,"First line of address is a required field\n");
		check += validate_required(txtPostCode,"Post Code is a required field\n");
		check += validate_email(txtEmail,"Not a valid e-mail address!\n");
		check += validate_duplicatefield(txtEmail,txtEmailConfirm,"Please confirm your email address\n");
		if (check!=""){
			alert(check);
			return false;
		}
		var loc = String(document.location.href).substring(7);
		loc = loc.substring(0,loc.indexOf("/"));
		var liveurl = String("packages.sky.com");
		if (loc != liveurl) {
			var rtn = "http://"+loc+String(ReturnUrl.value).substring(liveurl.length+7);
			ReturnUrl.value = rtn;
		}
	}
}

function visualUserFeedback(regularExpression){
    var number = document.getElementById('ctl00_MainContentPlaceHolder_AvailabilityCheck1_landNumber').value;
    var regExp = new RegExp(regularExpression);
    var result = regExp.exec(number.replace(/\s+/g,''));

    if (result[0]==number){
        var sHTML = '<img src="'+ oImage.src +'" width="16" height="16" alt="Checking your broadband options" /><p>Checking your broadband options...</p>'
        var eContainer = document.getElementById('dslUserFeedback');
        var sInputValue = document.getElementById('ctl00_MainContentPlaceHolder_AvailabilityCheck1_landNumber').value;
        var eDslMessage = document.getElementById('ctl00_MainContentPlaceHolder_AvailabilityCheck1_dslMessage');

        if(sInputValue != "Your landline number") {
            eDslMessage.innerHTML = '';  
            eContainer.innerHTML = sHTML;
            if(document.getElementById('talkNumber')){
                document.getElementById('talkNumber').getElementsByTagName('input')[0].value = sInputValue;
            }
        }
        
        if(document.getElementById('talkNumber')==null){
            document.getElementById('ctl00_MainContentPlaceHolder_AvailabilityCheck1_errorMsgs').style.visibility = "hidden";
        }

        return true;
    }
    return false;         
 }