function booking_is_valid()
{
    var message         = '';
    var arrivalDate     = document.getElementById('arrival-date');
    var numberOfNights  = document.getElementById('number-of-nights');
    var firstname       = document.getElementById('first-name');
    var surname         = document.getElementById('surname');
    var telephone       = document.getElementById('telephone');
    var mobile          = document.getElementById('mobile');
    var emailAddress    = document.getElementById('email-address');
    var poolSpa         = document.getElementById('pool-spa');
    var iAgree          = document.getElementById('i-agree');
    var depositMethod   = document.getElementById('deposit-method');
    var paymentCurrency = document.getElementById('payment-currency');
    var howFound        = document.getElementById('how-found');
    
    if ( arrivalDate.value.length == 0 )
        message += '- Please enter an arrival date\n';

    if ( numberOfNights.selectedIndex == 0 )
        message += '- Please choose a number of nights\n';
        
    if ( firstname.value.length == 0 )
        message += '- Please enter your first name\n';
        
    if ( surname.value.length == 0 )
        message += '- Please enter your surname\n';
        
    if ( telephone.value.length == 0 )
        message += '- Please enter your telephone contact number\n';
        
    if ( mobile.value.length == 0 )
        message += '- Please enter your mobile number\n';
        
    if ( emailAddress.value.length == 0 )
        message += '- Please enter your email address\n';
        
    if ( iAgree.checked == false )
        message += '- Please indicate that you agree to our Terms and Conditions\n';
    
    if ( depositMethod.selectedIndex == 0 )
        message += '- Please indicate your method of payment\n';
        
    if ( paymentCurrency.selectedIndex == 0 )
        message += '- Please enter your preferred payment currency\n';        
    
    if ( message.length > 0 )
    {
        alert(message);
        return false;
    }
    
    return true;
}