ajax封装函数和表单序列化

//表单序列化
function iSerialize(form){
   var parts={};
   for(var i=0;i<form.elements.length;i++){
      var filed=form.elements[i];
      switch(filed.type){
         case undefined:
         case "submit":
         case "reset":
         case "file":
         case "button":
            break;
         case "radio":
         case "checkbox":
            if(!filed.selected) break;
         case "select-one":
         case "select-multiple":
         for(var j=0;j<filed.options.length;j++){
            var option=filed.options[j];
            if(option.selected){
               var optValue="";
               if(option.hasAttribute){
                  optValue=(option.hasAttribute("value")?option.value:option.text);  
               }else{
                  optValue=(option.attributes("value").specified?option.value:option.text);  
               }
               parts[filed.name]=optValue;
            }
         }
         break;
         default:
            parts[filed.name]=filed.value;
      }
   }
   return parts;
}

//封装ajax
function iAjax(obj) {
   var xhr = (function () {
      if (typeof XMLHttpRequest != 'undefined') {
         return new XMLHttpRequest();
      } else if (typeof ActiveXObject != 'undefined') {
         var version = [
                              'MSXML2.XMLHttp.6.0',
                              'MSXML2.XMLHttp.3.0',
                              'MSXML2.XMLHttp'
         ];
         for (var i = 0; version.length; i ++) {
            try {
               return new ActiveXObject(version[i]);
            } catch (e) {
               //跳过
            }  
         }
      } else {
         throw new Error('您的系统或浏览器不支持XHR对象！');
      }
   })();
   obj.url = obj.url + '?rand=' + Math.random();
   obj.data = (function (data) {
      var arr = [];
      for (var i in data) {
         arr.push(encodeURIComponent(i) + '=' + encodeURIComponent(data[i]));
      }
      return arr.join('&');
   })(obj.data);
   if (obj.method === 'get') obj.url += obj.url.indexOf('?') == -1 ? '?' + obj.data : '&' + obj.data;
   if (obj.async === true) {
      xhr.onreadystatechange = function () {
         if (xhr.readyState == 4) {
            callback();
         }
      };
   }
   xhr.open(obj.method, obj.url, obj.async);
   if (obj.method === 'post') {
      xhr.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
      xhr.send(obj.data);    
   } else {
      xhr.send(null);
   }
   if (obj.async === false) {
      callback();
   }
   function callback() {
      if (xhr.status == 200) {
         obj.success(xhr.responseText);       //回调传递参数
      } else {
         alert('获取数据错误！错误代号：' + xhr.status + '，错误信息：' + xhr.statusText);
      }  
   }
}