数据请求（ajax）

/**
* GET请求
*/
var http = new XMLHttpRequest();
http.open('get','http://abc.com/api?id=1',true);
http.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=utf-8");
http.addEventListener('readystatechange',onStateEvent)
http.send(null);

    /**
     * POST请求
     */
    var http = new XMLHttpRequest();
    http.open('post','http://abc.com/api',true);
    http.setRequestHeader("Content-Type","application/x-www-form-urlencoded; charset=utf-8"); 
    http.addEventListener('readystatechange',onStateEvent)
    http.send('{"id":"1"}');
    
    
    /**
     * 请求状态
     */
    function onStateEvent(e)
    {
        if (this.readyState == 4 && this.status == 200)
        {
            console.log(this.responseText);
            console.log('请求成功')
        }
        
        if(this.readyState == 4 && this.status == 404)
        {
            console.log('请求失败')
        }
    }