function bookPresentationAjax(){
    
    error = $('bookFormError');
    error.update("");
    
    var name = $F('name');
    var email = $F('bookingEmail');
    var phone = $F('phone');
    var type = Form.getInputs('bookPresentationForm','radio','type').find(function(radio) { return radio.checked; }).value;
    var date = $F('date');
    var time = $F('time');
        
    var errors = new Array();
    
    if(name == ''){
       errors.push('Please specify your name');     
    }

    if(email == ''){
       errors.push('Please specify your email address');
    }else if(!validateEmail(email)){
       errors.push('Please specify a valid email');     
    }
    
    if(phone == ''){
       errors.push('Please specify your contact phone number');
    }
    
    if(errors.length > 0){
       showErrors(errors);
       return false;
    }
    
    
    $('loader').show();
    $('loader').update('<img src="images/ajax-loader-large.gif" />');
    $('submitBooking').hide();
 
    var url = 'scripts/book_presentation.php';
    var params = {name: name, email: email, phone: phone, type: type, date: date, time: time};
    new Ajax.Request(url, {
      method: 'post', parameters: params, onFailure: reportError,
      onSuccess: function(transport) {
        var response = transport.responseText;
        if(response.match('success') != null){
            $('loader').update("<img src='images/tick.gif' />Booking request sent successfully.");

        }else{
            $('loader').hide();
            $('submitBooking').show();
                       
            if(response.indexOf('Unexpected') >= 0){
                error.update(response);
                exit; 
            }
            
            //display errors
            errors = response.split(':');
            showErrors(errors);

        }
      }
    });

    return false;
    
}


function showErrors(errors){
    error = $('bookFormError');
    
    errors.each(function(item) {
       error.update(error.innerHTML + '<br />' + item);
    });
       
}



function validateEmail(email){
   var emailRegEx = /^([a-zA-Z0-9_\.\-])+\@(([a-zA-Z0-9\-])+\.)+([a-zA-Z0-9]{2,4})+$/;
   if(email.match(emailRegEx)){
      return true;
   }else{
      return false;
   }
}