将 JSON 发送到服务器并返回 JSON，无需 JQuery

2022-01-15 00:00:00 json post get xmlhttprequest javascript

我需要向服务器发送一个 JSON(我可以对其进行字符串化)并在用户端检索生成的 JSON，而不使用 JQuery.

I need to send a JSON (which I can stringify) to the server and to retrieve the resulting JSON on the user side, without using JQuery.

如果我应该使用 GET，我如何将 JSON 作为参数传递?会不会有太长的风险?

If I should use a GET, how do I pass the JSON as a parameter? Is there a risk it would be too long?

如果我应该使用 POST，如何在 GET 中设置等效的 onload 函数?

If I should use a POST, how do I set the equivalent of an onload function in GET?

或者我应该使用其他方法吗?

Or should I use a different method?

备注

这个问题不是关于发送一个简单的 AJAX.它不应该作为重复关闭.

This question is not about sending a simple AJAX. It should not be closed as duplicate.

推荐答案

使用POST方式发送和接收JSON格式数据

// Sending and receiving data in JSON format using POST method
//
var xhr = new XMLHttpRequest();
var url = "url";
xhr.open("POST", url, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function () {
    if (xhr.readyState === 4 && xhr.status === 200) {
        var json = JSON.parse(xhr.responseText);
        console.log(json.email + ", " + json.password);
    }
};
var data = JSON.stringify({"email": "hey@mail.com", "password": "101010"});
xhr.send(data);

使用 GET 方法发送和接收 JSON 格式的数据

// Sending a receiving data in JSON format using GET method
//      
var xhr = new XMLHttpRequest();
var url = "url?data=" + encodeURIComponent(JSON.stringify({"email": "hey@mail.com", "password": "101010"}));
xhr.open("GET", url, true);
xhr.setRequestHeader("Content-Type", "application/json");
xhr.onreadystatechange = function () {
    if (xhr.readyState === 4 && xhr.status === 200) {
        var json = JSON.parse(xhr.responseText);
        console.log(json.email + ", " + json.password);
    }
};
xhr.send();

使用 PHP 在服务器端处理 JSON 格式的数据

<?php
// Handling data in JSON format on the server-side using PHP
//
header("Content-Type: application/json");
// build a PHP variable from JSON sent using POST method
$v = json_decode(stripslashes(file_get_contents("php://input")));
// build a PHP variable from JSON sent using GET method
$v = json_decode(stripslashes($_GET["data"]));
// encode the PHP variable to JSON and send it back on client-side
echo json_encode($v);
?>

HTTP Get 请求的长度限制取决于所使用的服务器和客户端(浏览器)，从 2kB 到 8kB.如果 URI 比服务器可以处理的长，服务器应该返回 414(Request-URI Too Long)状态.

The limit of the length of an HTTP Get request is dependent on both the server and the client (browser) used, from 2kB - 8kB. The server should return 414 (Request-URI Too Long) status if an URI is longer than the server can handle.

注意 有人说我可以用状态名代替状态值；换句话说，我可以使用 xhr.readyState === xhr.DONE 而不是 xhr.readyState === 4 问题是 Internet Explorer 使用不同的状态名称，所以它是更好地使用状态值.

Note Someone said that I could use state names instead of state values; in other words I could use xhr.readyState === xhr.DONE instead of xhr.readyState === 4 The problem is that Internet Explorer uses different state names so it's better to use state values.

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