myajax.get({
<span style="white-space:pre"> </span>data: {}, //参数
 url: "", //请求地址
 //发生错误是调用
 error: function(data) {
 },
 //请求成功调用
 success: function(data){  
<span style="white-space:pre"> </span>//eval(data); 将字符串转换成json
 }
});

myajax.post({
 data: {}, //参数
 url: "", //
 //发生错误是调用
 error: function(data) {
 },
 //请求成功调用
 success: function(data){
 //eval(data); 将字符串转换成json
 }
});

myajax.getJSONP({
//参数
data: {
},
url: "", //请求地址
//请求成功调用
success: function(data) {
},
//发生错误时调用
error: function() {
}
});

var myajax = {

 post: function(params){
  var xmlhttp = this.createXMLHttpRequest();
  if (xmlhttp != null)
  {
   var async = true;
   if (typeof params.async != "undefined")
    async = params.async;
   var data = null;
   if (typeof params.data != "undefined")
    data = params.data;
   var url = "";
   if (typeof params.url != "undefined")
    url = params.url;
   if (url == null || url.length == 0)
    return;
   xmlhttp.open("POST", url, async);
   if (async){
    xmlhttp.onreadystatechange = function(){
    
     if (this.readyState==4){
      if (this.status==200){

       if (typeof params.success != "undefined") {
        params.success(xmlhttp.responseText);
       }
      }
      else {
       if (typeof params.error != "undefined") {
        params.error(xmlhttp.status + xmlhttp.statusText);
       }
       console.error(url + ": " + xmlhttp.status);
      }
     }
    };
   }
   
   xmlhttp.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
   var param = "";
   for (var prop in data) {
    param += prop + "=" + data[prop] + "&";
   }
   param = param.substring(0, param.length - 1);
   xmlhttp.send(param);
   if (!async) {
    
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
  
     if (typeof params.success != "undefined") {
      params.success(xmlhttp.responseText);
     }
    else {
     if (typeof params.error != "undefined") {
      params.error(xmlhttp.status + xmlhttp.statusText);
     }
     console.error(url + ": " + xmlhttp.status);
    }
    
   }
  }
 },
 get: function(params){
  var xmlhttp = this.createXMLHttpRequest();
  if (xmlhttp != null)
  {
   var async = true;
   if (params.async != undefined)
    async = params.async;
   var url = "";
   if (params.url != undefined)
    url = params.url;
   if (url == null || url.length == 0)
    return;
   if (params.data != null) {
    var data = params.data;
    var paramPrefix = url.indexOf("?") == -1 ? "?" : "&";
  
    url = url + paramPrefix;
    for (var prop in data) {
     url += prop + "=" + data[prop] + "&";
    }
    url = url.substring(0, url.length - 1);
   }
   xmlhttp.open("GET", url, async);
   if (async){
    xmlhttp.onreadystatechange = function(){
     if (this.readyState==4){
      if (this.status==200){
       if (typeof params.success != "undefined") {
        params.success(xmlhttp.responseText);
       }
      }
      else {
       if (typeof params.error != "undefined") {
        params.error(xmlhttp.status + xmlhttp.statusText);
       }
       console.error(url + ": " + xmlhttp.status);
      }
     }
    };
   }

   xmlhttp.send(null);
   if (!async) {
    if (xmlhttp.readyState == 4 && xmlhttp.status == 200)
     if (typeof params.success != "undefined") {
      params.success(xmlhttp.responseText);
     }
    else {
     if (typeof params.error != "undefined") {
      params.error(xmlhttp.status + xmlhttp.statusText);
     }
     console.error(url + ": " + xmlhttp.status);
    }
      
    
   }
  }
 },
 createXMLHttpRequest: function(){
  if (window.XMLHttpRequest)
  {
   return new XMLHttpRequest();
  }
  else if (window.ActiveXObject)
  {
  //code for IE5 and IE6
   return new ActiveXObject("Microsoft.XMLHTTP");
  }
  return null;
 },
 getJSONP: function(params) {

  var url = null;
  if (typeof params.url != "undefined") {
   url = params.url;
  }
  if (url == null) {
   return;
  }
  
  var ff = "" + new Date().getTime() + (parseInt(Math.random() * 10000000000));
  eval("jsonpCallback_" + ff + "=" + function(data){
 
   if (typeof params.success != "undefined") {
    params.success(data);
   }
  });

  //根据url中是否出现过 "?" 来决定添加时间戳参数时使用 "?" 还是 "&" 
  var paramPrefix = url.indexOf("?") == -1 ? "?" : "&";

  url = url + paramPrefix + "jsonpCallback=" + "jsonpCallback_" + ff;
  var param = "";

  if (typeof params.data != "undefined" && params.data != null) {
  
   var data = params.data;
   for (var prop in data) {
    param += prop + "=" + data[prop] + "&";
   }
   param = param.substring(0, param.length - 1);
  }
  if (param.length > 0)
  url = url + "&" + param; 
  var script = document.createElement("script"); 
  document.body.appendChild(script); 
  script.src = url; 
  script.charset ="UTF-8";
  // for firefox, google etc.
  script.onerror = function() {
   if (typeof params.error != "undefined") {
    params.error();
   }
   
   }
  script.onload = function() {

  document.body.removeChild(script); 
  } 
  // for ie 
  script.onreadystatechange = function() { 
    if (this.readyState == "loaded" || this.readyState == "complete") { 
      document.body.removeChild(script);
    } 
  }
 }

};