为什么下面的post没问题，但是put请求会报错：
XMLHttpRequest cannot load http://localhost:8001/service. Response to preflight request doesn't pass access control check: No 'Access-Control-Allow-Origin' header is present on the requested resource. Origin 'http://localhost:63343' is therefore not allowed access.
客户端
$.ajax({
url: 'http://localhost:8001/man',
method: 'POST',
success: function (data) {
console.log(data)
}
});
$.ajax({
url: 'http://localhost:8001/service',
method: 'PUT',
success: function (data) {
console.log(data)
}
});
服务端
app.post('/man', function (req, res) {
var body = req.body;
console.log(body);
if (body) {
res.header("Content-Type", "application/json; charset=utf-8");
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "GET, POST, PATCH, PUT, DELETE, OPTIONS");
res.send(body);
}
});
app.put('/service', function (req, res) {
res.header("Content-Type", "application/json; charset=utf-8");
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "GET, POST, PATCH, PUT, DELETE, OPTIONS");
res.send(req.body);
});