How to implement Ajax in native JavaScript_javascript skills-JS Tutorial-php.cn

How to implement Ajax in native JavaScript_javascript skills

WBOY

Release： 2016-05-16 15:06:16

Original

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First of all, I share the native JavaScript Ajax code for your reference. The specific content is as follows

var getXmlHttpRequest = function() {
  if (window.XMLHttpRequest) {
    //主流浏览器提供了XMLHttpRequest对象
    return new XMLHttpRequest();
  } else if (window.ActiveXObject) {
    //低版本的IE浏览器没有提供XMLHttpRequest对象
    //所以必须使用IE浏览器的特定实现ActiveXObject
    return new ActiveXObject("Microsoft.XMLHttpRequest");
  }

};
var xhr = getXmlHttpRequest();
xhr.onreadystatechange = function() {
  console.log(xhr.readyState);
  if (xhr.readyState === 3 && xhr.status === 200) {
    //获取成功后执行操作
    //数据在xhr.responseText
    console.log(xhr.responseText);
  }
};
xhr.open("get", "data.php", true);
xhr.send("");

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Let me share with you several ways to use javascript to implement native ajax.
Before implementing ajax, you must create an XMLHttpRequest object. If the browser that created the object does not support it, you need to create an ActiveXObject as follows:

var xmlHttp; 
function createxmlHttpRequest() { 
if (window.ActiveXObject) { 
xmlHttp = new ActiveXObject("Microsoft.XMLHTTP"); 
} else if (window.XMLHttpRequest) { 
xmlHttp=new XMLHttpRequest(); 
}

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(1) Use the xmlHttp created above to implement the simplest ajax get request:

function doGet(url){ 
// 注意在传参数值的时候最好使用encodeURI处理一下，以防出现乱码 
createxmlHttpRequest(); 
xmlHttp.open("GET",url); 
xmlHttp.send(null); 
xmlHttp.onreadystatechange = function() { 
if ((xmlHttp.readyState == 4) && (xmlHttp.status == 200)) { 
alert('success'); 
} else { 
alert('fail'); 
} 
} 
}

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(2) Use the xmlHttp created above to implement the simplest ajax post request:

function doPost(url,data){ 
// 注意在传参数值的时候最好使用encodeURI处理一下，以防出现乱码 
createxmlHttpRequest(); 
xmlHttp.open("POST",url); 
xmlHttp.setRequestHeader("Content-Type","application/x-www-form-urlencoded"); 
xmlHttp.send(data); 
xmlHttp.onreadystatechange = function() { 
if ((xmlHttp.readyState == 4) && (xmlHttp.status == 200)) { 
alert('success'); 
} else { 
alert('fail'); 
} 
} 
}

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The above is the entire content of this article, I hope it will be helpful to everyone’s study.