xhr封装

title: xhr封装
date: 2019-09-07 07:23:19
tags: JavaScript
categories:

• 前端

• 网络请求

// POST
var xhr;
if (window.XMLHttpRequest) { 
    // Mozilla, Safari...
  xhr = new XMLHttpRequest();
} else if (window.ActiveXObject) { 
    // IE
  try {
    xhr = new ActiveXObject('Msxml2.XMLHTTP');
  } catch (e) {    try {
      xhr = new ActiveXObject('Microsoft.XMLHTTP');
    } catch (e) {}
  }
}
<!--more-->
if (xhr) {
  xhr.onreadystatechange = onReadyStateChange;
  xhr.open('POST', '/api', true);  // 设置 Content-Type 为 application/x-www-form-urlencoded
  // 以表单的形式传递数据
  xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
  xhr.send('username=admin&password=root');
}
// onreadystatechange 方法
function onReadyStateChange() {  
    // 该函数会被调用四次
    console.log(xhr.readyState);  
    if (xhr.readyState === 4) {    
        // everything is good, the response is received
        if (xhr.status === 200) {     
            console.log(xhr.responseText);
        } else {      
            console.log('There was a problem with the request.');
    }
  } else {    
    // still not ready
    console.log('still not ready...');
  }
}

额，兼容浏览器的写法。多少留一份，万一忘了，对吧。