$ = { ajax:function(options){ var xhr = null, // XXMLHttpRequest对象 url = options.url, // url 地址 method = options.method || 'GET', // 传输方式，默认GET async = typeof (options.async) === "undefined"?true:options.async, data = options.data || null, params = '', //传递的参数 callback = options.success, error = options.error; // 将data的对象字面量的形式转化为字符串形式 if(data){ for(var i in data){ params += i + '=' + data[i] + '&'; } params = params.replace(/&$/,''); }
// 根据method 的值改变URL
if(method === 'GET'){
url += '?' + params;
}
if(typeof XMLHttpRequest != "undefined"){
xhr = new XMLHttpRequest();
}else if(typeof ActiveXObject != "undefined"){
var xhrArr = ['Microsoft.XMLHTTP', 'MSXML2.XMLHTTP.6.0', 'MSXML2.XMLHTTP.5.0',
'MSXML2.XMLHTTP.4.0', 'MSXML2.XMLHTTP.3.0', 'MSXML2.XMLHTTP.2.0',]
var len = xhrArr.length;
for(var i=0; i <=len; i++){
try{
xhr = new ActiveXObject(xhrArr[i])
break
}catch(e){
//TODO handle the exception
}
}
}else{
throw new Error('No XHR object available.');
}
xhr.onreadystatechange = function(){
if xhr.readyState === 4){
if((xhr.status >=200 && xhr.status <300) || xhr.status===304){
callback && callback(JSON.parse(xhr.responseText))
}else{
error && error();
}
}
}
// 创建发送请求
xhr.open(method,url,async)
xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
xhr.send(params);
}
}
