[e1f]

KaizZzer, date != data :

$.ajax({ 
    type: 'POST',
    url: 'corner.php', 
    data: {color: colorv, radius: radiusv,type: typev, format: formatv},
    dat*!*a*/!*Type: 'json', 
    success: function(data){
        alert(data.ru);
    }
});