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 chkOrder_page1(sheet) {
    if (document.sheet.m_product.value=="0") {
        alert(errorNoProduct);
        document.sheet.m_product.focus();
        return false;
    
    } else if (document.sheet.m_orderType.value=="0") {
        alert(errorNoOrderType);
        document.sheet.m_orderType.focus();
        return false; 

    }    
    return true;
}

function chkOrder_page2(sheet) {
    if (document.sheet.m_why.value=="0") {
        alert(errorNoWhy);
        document.sheet.m_why.focus();
        return false;
    
    } else if (document.sheet.m_function.value=="0") {
        alert(errorNoFunction);
        document.sheet.m_function.focus();
        return false; 
        
    } else if (document.sheet.m_wants.value=="") {
        alert(errorNoWants);
        document.sheet.m_wants.focus();
        return false;         

    }    
    return true;
}

function chkOrder_page3(sheet) {
    if (document.sheet.m_name.value=="") {
        alert(errorNoName);
        document.sheet.m_name.focus();
        return false;
    
    } else if (document.sheet.m_email.value=="" && document.sheet.m_phone.value=="") {
        alert(errorNoContact);
        document.sheet.m_phone.focus();        
        return false; 

    } else if (document.sheet.m_email.value!="") {
        
        if (!validEmail(document.sheet.m_email.value)) {
          alert(errorNoValidEmail);
          document.sheet.m_email.focus();
          return false;
        }        
        
    }    
    return true;
}