如何使用JavaScript进行AJAX调用,而不使用jQuery?
当前回答
From youMightNotNeedJquery.com + JSON.stringify
var request = new XMLHttpRequest();
request.open('POST', '/my/url', true);
request.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
request.send(JSON.stringify(data));
其他回答
xhttp.onreadystatechange = function() {
if (this.readyState == 4 && this.status == 200) {
alert(this.responseText);
}
};
xhttp.open("GET", "ajax_info.txt", true);
xhttp.send();
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。
使用“vanilla”(普通)JavaScript:
function loadXMLDoc() {
var xmlhttp = new XMLHttpRequest();
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == XMLHttpRequest.DONE) { // XMLHttpRequest.DONE == 4
if (xmlhttp.status == 200) {
document.getElementById("myDiv").innerHTML = xmlhttp.responseText;
}
else if (xmlhttp.status == 400) {
alert('There was an error 400');
}
else {
alert('something else other than 200 was returned');
}
}
};
xmlhttp.open("GET", "ajax_info.txt", true);
xmlhttp.send();
}
jQuery:
$.ajax({
url: "test.html",
context: document.body,
success: function() {
$(this).addClass("done");
}
});
如果您不想包含JQuery,我建议您尝试一些轻量级AJAX库。
我最喜欢的是reqwest。它只有3.4kb,构建得非常好:https://github.com/ded/Reqwest
下面是一个带有reqwest的GET请求示例:
reqwest({
url: url,
method: 'GET',
type: 'json',
success: onSuccess
});
现在,如果您想要更轻量级的东西,我将尝试仅需0.4kb的microAjax: https://code.google.com/p/microajax/
这是所有的代码:
function microAjax(B,A){this.bindFunction=function(E,D){return function(){return E.apply(D,[D])}};this.stateChange=function(D){if(this.request.readyState==4){this.callbackFunction(this.request.responseText)}};this.getRequest=function(){if(window.ActiveXObject){return new ActiveXObject("Microsoft.XMLHTTP")}else{if(window.XMLHttpRequest){return new XMLHttpRequest()}}return false};this.postBody=(arguments[2]||"");this.callbackFunction=A;this.url=B;this.request=this.getRequest();if(this.request){var C=this.request;C.onreadystatechange=this.bindFunction(this.stateChange,this);if(this.postBody!==""){C.open("POST",B,true);C.setRequestHeader("X-Requested-With","XMLHttpRequest");C.setRequestHeader("Content-type","application/x-www-form-urlencoded");C.setRequestHeader("Connection","close")}else{C.open("GET",B,true)}C.send(this.postBody)}};
下面是一个示例调用:
microAjax(url, onSuccess);
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()。