Email prüfen mit filter_var

        $("#confirm").on("click", function()                                    
        {                                                                                     
            var email = document.getElementById("email").value;                 
            console.log(email);                   
                                                                                
            var ajax_params = {                                                 
                'option' : 'com_ajax',                                          
                'module' : 'book_paypal',                                       
                'format' : 'json',                                              
                'function' : 'confirm',                                         
                'email' : email                                                                                              
            };                                                                  
                                                                                
            $.ajax(                                                             
            {                                                                   
                type: "POST",                                                   
                data: ajax_params,                                              
                context: this,                                                  
                success: function(response)                                     
                {                                                               
                    if (response.success)                                       
                    {                                                           
                        alert(response.data);                  
                    }                                                           
                    else                                                        
                    {                                                           
                        alert('Something went wrong.');                         
                    }                                                           
                },                                                              
                error: function()                                               
                {                                                               
                    alert('AJAX Error...);                                     
                }                                                               
            });