如何使用XMLHttpRequest加载本地json文件

ES5版本

// required use of an anonymous callback, // as .open() will NOT return a value but simply returns undefined in asynchronous mode! function loadJSON(callback) { var xObj = new XMLHttpRequest(); xObj.overrideMimeType("application/json"); xObj.open('GET', './data.json', true); // 1. replace './data.json' with the local path of your file xObj.onreadystatechange = function() { if (xObj.readyState === 4 && xObj.status === 200) { // 2. call your callback function callback(xObj.responseText); } }; xObj.send(null); } function init() { loadJSON(function(response) { // 3. parse JSON string into JSON Object console.log('response =', response); var json = JSON.parse(response); console.log('your local JSON =', JSON.stringify(json, null, 4)); // 4. render to your page const app = document.querySelector('#app'); app.innerHTML = '<pre>' + JSON.stringify(json, null, 4) + '</pre>'; }); } init(); <section id="app"> loading... </section>

ES6版本

// required use of an anonymous callback, // as .open() will NOT return a value but simply returns undefined in asynchronous mode! const loadJSON = (callback) => { const xObj = new XMLHttpRequest(); xObj.overrideMimeType("application/json"); // 1. replace './data.json' with the local path of your file xObj.open('GET', './data.json', true); xObj.onreadystatechange = () => { if (xObj.readyState === 4 && xObj.status === 200) { // 2. call your callback function callback(xObj.responseText); } }; xObj.send(null); } const init = () => { loadJSON((response) => { // 3. parse JSON string into JSON Object console.log('response =', response); const json = JSON.parse(response); console.log('your local JSON =', JSON.stringify(json, null, 4)); // 4. render to your page const app = document.querySelector('#app'); app.innerHTML = `<pre>${JSON.stringify(json, null, 4)}</pre>`; }); } init(); <section id="app"> loading... </section>

在线演示

https://cdn.xgqfrms.xyz/ajax/XMLHttpRequest/index.html

如果您正在使用JSON的本地数组-正如您在问题(test.json)中的示例中所示，那么您可以使用JQuery的parseJSON()方法->

var obj = jQuery.parseJSON('{"name":"John"}');
alert( obj.name === "John" );

getJSON()用于从远程站点获取JSON -它不会在本地工作(除非您使用本地HTTP服务器)

我只是稍微编辑了一下JSON文件。

myfile。Json => myfile.js

在JSON文件中，(将其设置为JS变量)

{name: "Whatever"} => var x = {name: "Whatever"}

最后，

导出默认x;

然后,

导入JsonObj from './myfile.js';

美元。getJSON只适用于我在Chrome 105.0.5195.125使用等待，这是一个脚本类型的模块。

<script type="module">
    const myObject = await $.getJSON('./myObject.json');
    console.log('myObject: ' + myObject);
</script>

无须等待，我看到:

Uncaught TypeError: myObject is not iterable

当解析myObject时。

没有type="module"我看到:

Uncaught SyntaxError: await is only valid in async functions and the top level bodies of modules

function readTextFile(srcfile) {
        try { //this is for IE
            var fso = new ActiveXObject("Scripting.FileSystemObject");;
            if (fso.FileExists(srcfile)) {
                var fileReader = fso.OpenTextFile(srcfile, 1);
                var line = fileReader.ReadLine();
                var jsonOutput = JSON.parse(line); 
            }

        } catch (e) {

        }
}

readTextFile("C:\\Users\\someuser\\json.txt");

我所做的是，首先，从network选项卡，记录服务的网络流量，从响应体，复制并保存json对象到本地文件中。然后用本地文件名调用函数，你应该能够在上面的jsonOutout中看到json对象。

如何使用XMLHttpRequest加载本地json文件

ES5版本

// required use of an anonymous callback, // as .open() will NOT return a value but simply returns undefined in asynchronous mode! function loadJSON(callback) { var xObj = new XMLHttpRequest(); xObj.overrideMimeType("application/json"); xObj.open('GET', './data.json', true); // 1. replace './data.json' with the local path of your file xObj.onreadystatechange = function() { if (xObj.readyState === 4 && xObj.status === 200) { // 2. call your callback function callback(xObj.responseText); } }; xObj.send(null); } function init() { loadJSON(function(response) { // 3. parse JSON string into JSON Object console.log('response =', response); var json = JSON.parse(response); console.log('your local JSON =', JSON.stringify(json, null, 4)); // 4. render to your page const app = document.querySelector('#app'); app.innerHTML = '<pre>' + JSON.stringify(json, null, 4) + '</pre>'; }); } init(); <section id="app"> loading... </section>

ES6版本

// required use of an anonymous callback, // as .open() will NOT return a value but simply returns undefined in asynchronous mode! const loadJSON = (callback) => { const xObj = new XMLHttpRequest(); xObj.overrideMimeType("application/json"); // 1. replace './data.json' with the local path of your file xObj.open('GET', './data.json', true); xObj.onreadystatechange = () => { if (xObj.readyState === 4 && xObj.status === 200) { // 2. call your callback function callback(xObj.responseText); } }; xObj.send(null); } const init = () => { loadJSON((response) => { // 3. parse JSON string into JSON Object console.log('response =', response); const json = JSON.parse(response); console.log('your local JSON =', JSON.stringify(json, null, 4)); // 4. render to your page const app = document.querySelector('#app'); app.innerHTML = `<pre>${JSON.stringify(json, null, 4)}</pre>`; }); } init(); <section id="app"> loading... </section>

在线演示

https://cdn.xgqfrms.xyz/ajax/XMLHttpRequest/index.html