如何使用JavaScript进行AJAX调用，而不使用jQuery?
当前回答
这个版本在普通ES6/ES2015中怎么样?
function get(url) {
return new Promise((resolve, reject) => {
const req = new XMLHttpRequest();
req.open('GET', url);
req.onload = () => req.status === 200 ? resolve(req.response) : reject(Error(req.statusText));
req.onerror = (e) => reject(Error(`Network Error: ${e}`));
req.send();
});
}
函数返回一个promise。下面是一个关于如何使用该函数并处理它返回的承诺的示例:
get('foo.txt')
.then((data) => {
// Do stuff with data, if foo.txt was successfully loaded.
})
.catch((err) => {
// Do stuff on error...
});
如果你需要加载一个json文件，你可以使用json .parse()将加载的数据转换为JS对象。
您还可以集成req。responseType='json'到函数中，但不幸的是，没有IE支持它，所以我将坚持使用json .parse()。
其他回答
现在在现代浏览器中有一个更好的本机Fetch API可用。fetch()方法允许您发出web请求。 例如，从/get-data请求一些JSON:
let options = {
method: 'GET',
headers: {}
};
fetch('/get-data', options)
.then(response => response.json())
.then(body => {
// Do something with body
});
更多细节请参见MDN Web Docs: Using Fetch API。
HTML:
<!DOCTYPE html>
<html>
<head>
<script>
function loadXMLDoc()
{
var xmlhttp;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
if (xmlhttp.readyState==4 && xmlhttp.status==200)
{
document.getElementById("myDiv").innerHTML=xmlhttp.responseText;
}
}
xmlhttp.open("GET","1.php?id=99freebies.blogspot.com",true);
xmlhttp.send();
}
</script>
</head>
<body>
<div id="myDiv"><h2>Let AJAX change this text</h2></div>
<button type="button" onclick="loadXMLDoc()">Change Content</button>
</body>
</html>
PHP:
<?php
$id = $_GET[id];
print "$id";
?>
这只是一个简单的4步过程，
我希望这对你们有帮助
步骤1。存储对XMLHttpRequest对象的引用
var xmlHttp = createXmlHttpRequestObject();
步骤2。检索XMLHttpRequest对象
function createXmlHttpRequestObject() {
// will store the reference to the XMLHttpRequest object
var xmlHttp;
// if running Internet Explorer
if (window.ActiveXObject) {
try {
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
} catch (e) {
xmlHttp = false;
}
}
// if running Mozilla or other browsers
else {
try {
xmlHttp = new XMLHttpRequest();
} catch (e) {
xmlHttp = false;
}
}
// return the created object or display an error message
if (!xmlHttp)
alert("Error creating the XMLHttpRequest object.");
else
return xmlHttp;
}
步骤3。使用XMLHttpRequest对象进行异步HTTP请求
function process() {
// proceed only if the xmlHttp object isn't busy
if (xmlHttp.readyState == 4 || xmlHttp.readyState == 0) {
// retrieve the name typed by the user on the form
item = encodeURIComponent(document.getElementById("input_item").value);
// execute the your_file.php page from the server
xmlHttp.open("GET", "your_file.php?item=" + item, true);
// define the method to handle server responses
xmlHttp.onreadystatechange = handleServerResponse;
// make the server request
xmlHttp.send(null);
}
}
步骤4。当从服务器接收消息时自动执行
function handleServerResponse() {
// move forward only if the transaction has completed
if (xmlHttp.readyState == 4) {
// status of 200 indicates the transaction completed successfully
if (xmlHttp.status == 200) {
// extract the XML retrieved from the server
xmlResponse = xmlHttp.responseText;
document.getElementById("put_response").innerHTML = xmlResponse;
// restart sequence
}
// a HTTP status different than 200 signals an error
else {
alert("There was a problem accessing the server: " + xmlHttp.statusText);
}
}
}
var load_process = false;
function ajaxCall(param, response) {
if (load_process == true) {
return;
}
else
{
if (param.async == undefined) {
param.async = true;
}
if (param.async == false) {
load_process = true;
}
var xhr;
xhr = new XMLHttpRequest();
if (param.type != "GET") {
xhr.open(param.type, param.url, true);
if (param.processData != undefined && param.processData == false && param.contentType != undefined && param.contentType == false) {
}
else if (param.contentType != undefined || param.contentType == true) {
xhr.setRequestHeader('Content-Type', param.contentType);
}
else {
xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
}
}
else {
xhr.open(param.type, param.url + "?" + obj_param(param.data));
}
xhr.onprogress = function (loadTime) {
if (param.progress != undefined) {
param.progress({ loaded: loadTime.loaded }, "success");
}
}
xhr.ontimeout = function () {
this.abort();
param.success("timeout", "timeout");
load_process = false;
};
xhr.onerror = function () {
param.error(xhr.responseText, "error");
load_process = false;
};
xhr.onload = function () {
if (xhr.status === 200) {
if (param.dataType != undefined && param.dataType == "json") {
param.success(JSON.parse(xhr.responseText), "success");
}
else {
param.success(JSON.stringify(xhr.responseText), "success");
}
}
else if (xhr.status !== 200) {
param.error(xhr.responseText, "error");
}
load_process = false;
};
if (param.data != null || param.data != undefined) {
if (param.processData != undefined && param.processData == false && param.contentType != undefined && param.contentType == false) {
xhr.send(param.data);
}
else {
xhr.send(obj_param(param.data));
}
}
else {
xhr.send();
}
if (param.timeout != undefined) {
xhr.timeout = param.timeout;
}
else
{
xhr.timeout = 20000;
}
this.abort = function (response) {
if (XMLHttpRequest != null) {
xhr.abort();
load_process = false;
if (response != undefined) {
response({ status: "success" });
}
}
}
}
}
function obj_param(obj) {
var parts = [];
for (var key in obj) {
if (obj.hasOwnProperty(key)) {
parts.push(encodeURIComponent(key) + '=' + encodeURIComponent(obj[key]));
}
}
return parts.join('&');
}
我的ajax调用
var my_ajax_call=ajaxCall({
url: url,
type: method,
data: {data:value},
dataType: 'json',
async:false,//synchronous request. Default value is true
timeout:10000,//default timeout 20000
progress:function(loadTime,status)
{
console.log(loadTime);
},
success: function (result, status) {
console.log(result);
},
error :function(result,status)
{
console.log(result);
}
});
对于中止先前的请求
my_ajax_call.abort(function(result){
console.log(result);
});
<html>
<script>
var xmlDoc = null ;
function load() {
if (typeof window.ActiveXObject != 'undefined' ) {
xmlDoc = new ActiveXObject("Microsoft.XMLHTTP");
xmlDoc.onreadystatechange = process ;
}
else {
xmlDoc = new XMLHttpRequest();
xmlDoc.onload = process ;
}
xmlDoc.open( "GET", "background.html", true );
xmlDoc.send( null );
}
function process() {
if ( xmlDoc.readyState != 4 ) return ;
document.getElementById("output").value = xmlDoc.responseText ;
}
function empty() {
document.getElementById("output").value = '<empty>' ;
}
</script>
<body>
<textarea id="output" cols='70' rows='40'><empty></textarea>
<br></br>
<button onclick="load()">Load</button>
<button onclick="empty()">Clear</button>
</body>
</html>
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