VM619:1 Uncaught SyntaxError: Unexpected end of JSON input
    at JSON.parse (<anonymous>)
    at Http.onreadystatechange

function anidados() {
    var idpedido = document.getElementById("orden_produccion").value;
    var idcode = document.getElementById("idcode").value;

    var formData = new FormData(document.form)
    formData.append('id', idpedido);
    formData.append('code', idcode);

    const Http = new XMLHttpRequest();
    const url='index.php';
    Http.open("POST", url);
    Http.getResponseHeader("Content-Type", "application/json");
    Http.onreadystatechange = function(e){
        var data = Http.responseText;
        var obj = JSON.parse(data);
        console.log(data);
        document.getElementById('numero_tarima').innerHTML = obj.select1;
    }
    Http.send(formData);
}