function validEmail(email) {
    if (email=="" || email== null) {
        return false;
    } else {
        var emailReg = /^.+\@(\[?)[a-zA-Z0-9\-\.]+\.([a-zA-Z]{2,6}|[0-9]{1,3})(\]?)$/; // valid
        if (!emailReg.test(email)) { // if syntax is valid
            return false;
        }
        return true;
    }
}

function chkReg(registration) {
    if (document.registration.m_userNick.value=="") {
        alert(errorNoUserName);
        document.registration.m_userNick.focus();
        return false;
    
    } else if (document.registration.m_email.value=="") {
        alert(errorNoEmail);
        document.registration.m_email.focus();
        return false; 
        
    } if (!validEmail(registration.m_email.value)) {
        alert(errorNoValidEmail);
        registration.m_email.focus();
        return false;
                
    } else if (registration.m_email.value!=registration.m_email2.value) {
        alert(errorEmailsAreNotSame);
        registration.m_email2.focus();
        return false;
                
    } else if (document.registration.m_userPass1.value=="") {
        alert(errorNoPassword);
        document.registration.m_userPass1.focus();
        return false;       

    } else if (registration.m_userPass1.value!=registration.m_userPass2.value) {
        alert(errorMsgPasswordAreNotSame);
        registration.m_userPass1.value=""
        registration.m_userPass2.value=""
        registration.m_userPass1.focus();
        return false;

    }
    
    return true;
}



function chkRegMod(sheet) {
    if (document.sheet.m_userNick.value=="") {
        alert(errorNoUserName);
        document.sheet.m_userNick.focus();
        return false;  
        
    } else if (document.sheet.m_email.value=="") {
        alert(errorNoEmail);
        document.sheet.m_email.focus();
        return false;
        
    } if (!validEmail(sheet.m_email.value)) {
        alert(errorNoValidEmail);
        registration.m_email.focus();
        return false;             
        
    } else if (document.sheet.m_familyName.value=="") {
        alert(errorNoFamilyName);
        document.sheet.m_familyName.focus();
        return false; 
        
    } else if (document.sheet.m_firstName.value=="") {
        alert(errorNoFirstName);
        document.sheet.m_firstName.focus();
        return false; 
        
    } else if (document.sheet.m_bill_name.value=="") {
        alert(errorNoBillName);
        document.sheet.m_bill_name.focus();
        return false; 
        
    } else if (document.sheet.m_bill_city.value=="") {
        alert(errorNoBillCity);
        document.sheet.m_bill_city.focus();
        return false; 
        
    } else if (document.sheet.m_bill_postcode.value=="") {
        alert(errorNoBillPostcode);
        document.sheet.m_bill_postcode.focus();
        return false; 
        
    } else if (document.sheet.m_bill_address.value=="") {
        alert(errorNoBillAddress);
        document.sheet.m_bill_address.focus();
        return false;        


    } else if (document.sheet.m_phone.value=="") {
        alert(errorNoPhone);
        document.sheet.m_phone.focus();
        return false;            

        
    } else if (sheet.m_userPass1.value!=sheet.m_userPass2.value) {
        alert(errorMsgPasswordAreNotSame);
        sheet.m_userPass1.value=""
        sheet.m_userPass2.value=""
        sheet.m_userPass1.focus();
        return false;      
        
    }
    return true;
}



function chkCartAddress(sheet) {
  
    if (document.sheet.m_bill_name.value=="") {
        alert(errorNoBillName);
        document.sheet.m_bill_name.focus();
        return false; 
        
    } else if (document.sheet.m_bill_city.value=="") {
        alert(errorNoBillCity);
        document.sheet.m_bill_city.focus();
        return false; 
        
    } else if (document.sheet.m_bill_postcode.value=="") {
        alert(errorNoBillPostcode);
        document.sheet.m_bill_postcode.focus();
        return false; 
        
    } else if (document.sheet.m_bill_address.value=="") {
        alert(errorNoBillAddress);
        document.sheet.m_bill_address.focus();
        return false;        

    } else if (document.sheet.m_phone.value=="") {
        alert(errorNoPhone);
        document.sheet.m_phone.focus();
        return false;            

    } 
    return true;
}



function chkCartOrderAddress(sheet) {
  
    if (document.sheet.m_bill_name.value=="") {
        alert(errorNoBillName);
        document.sheet.m_bill_name.focus();
        return false; 
        
    } else if (document.sheet.m_bill_city.value=="") {
        alert(errorNoBillCity);
        document.sheet.m_bill_city.focus();
        return false; 
        
    } else if (document.sheet.m_bill_postcode.value=="") {
        alert(errorNoBillPostcode);
        document.sheet.m_bill_postcode.focus();
        return false; 
        
    } else if (document.sheet.m_bill_address.value=="") {
        alert(errorNoBillAddress);
        document.sheet.m_bill_address.focus();
        return false;        
        
    } else if (document.sheet.m_order_name.value=="") {
        alert(errorNoOrderName);
        document.sheet.m_order_name.focus();
        return false; 
        
    } else if (document.sheet.m_order_city.value=="") {
        alert(errorNoOrderCity);
        document.sheet.m_order_city.focus();
        return false; 
        
    } else if (document.sheet.m_order_postcode.value=="") {
        alert(errorNoOrderPostcode);
        document.sheet.m_order_postcode.focus();
        return false; 
        
    } else if (document.sheet.m_order_address.value=="") {
        alert(errorNoOrderAddress);
        document.sheet.m_order_address.focus();
        return false;        

    } else if (document.sheet.m_phone.value=="") {
        alert(errorNoPhone);
        document.sheet.m_phone.focus();
        return false;            

    } 
    return true;
}




function copyAddress() {
    with (document.sheet) {
    	m_order_name.value = m_bill_name.value;
    	m_order_city.value = m_bill_city.value;
    	m_order_postcode.value = m_bill_postcode.value;
    	m_order_address.value = m_bill_address.value;   
    }
}