jquery - ExpressJS jQuery ajax Post 不返回任何内容

Question

我试图从 Ajax post 请求返回一些值，但我在控制台中没有看到任何值。这里缺少什么？

express

app.post('/register',function(req,res) {
    //console.log(JSON.stringify(req.body)); // it works
    res.send(req.body); // it doesn't work on client side.
});

jQuery

$("#register").submit(function (e) {
    e.preventDefault();
    var data = {};
    data.username = $('#username').val();
    data.email = $('#email').val();
    data.password1 = $('#password1').val();
    data.password2 = $('#password2').val();
    if (data.password1 == data.password2) {
        alert("okay");
        $.ajax({
            type: 'POST',
            data: JSON.stringify(data),
            contentType: 'application/json',
            url: '/register',
            success: function (data) {
                console.log(data.username + data.email + data.password1 + data.password2); 
                // nothing returns, why?
            }
        });
    } else {
        $('.register-now').after('<div class="alert alert-danger" role="alert"> ' +
            'You entered two different passwords. ' +
            '</div>');
    }
});

Answer 1

你说我很困惑

but I don't see any values in console

但是你说

console.log(JSON.stringify(req.body)); // it works

什么给出了？