function sajax_do_call(func_name, args) {
      var i, x, n;
      var uri;
      var post_data;
      var target_id;
      
      sajax_debug("in sajax_do_call().." + sajax_request_type + "/" + sajax_target_id);
      target_id = sajax_target_id;
      if (typeof(sajax_request_type) == "undefined" || sajax_request_type == "")
        sajax_request_type = "GET";
      
      uri = "/sajax/example_date.php";//执行程序的uri
      //根据提交方式整理提交数据
      if (sajax_request_type == "GET") {
      
        if (uri.indexOf("?") == -1)
          uri += "?rs=" + escape(func_name);
        else
          uri += "&rs=" + escape(func_name);
        uri += "&rst=" + escape(sajax_target_id);
        uri += "&rsrnd=" + new Date().getTime();
        
        for (i = 0; i < args.length-1; i++)
          uri += "&rsargs[]=" + escape(args[i]);

        post_data = null;
      }
      else if (sajax_request_type == "POST") {
        post_data = "rs=" + escape(func_name);
        post_data += "&rst=" + escape(sajax_target_id);
        post_data += "&rsrnd=" + new Date().getTime();
        
        for (i = 0; i < args.length-1; i++)
          post_data = post_data + "&rsargs[]=" + escape(args[i]);
      }
      else {
        alert("Illegal request type: " + sajax_request_type);
      }
      
      x = sajax_init_object();//生成XMLHttpRequest对象
      if (x == null) {
        if (sajax_failure_redirect != "") {
          location.href = sajax_failure_redirect;
          return false;
        } else {
          sajax_debug("NULL sajax object for user agent:\n" + navigator.userAgent);
          return false;
        }
      } else {
        x.open(sajax_request_type, uri, true);
        // window.open(uri);
        
        sajax_requests[sajax_requests.length] = x;
        
        if (sajax_request_type == "POST") {
          x.setRequestHeader("Method", "POST " + uri + " HTTP/1.1");
          x.setRequestHeader("Content-Type", "application/x-www-form-urlencoded");
        }
        //callback，根据XMLHttpRequest程序的状态执行操作
        x.onreadystatechange = function() {
          if (x.readyState != 4)
            return;

          sajax_debug("received " + x.responseText);
        
          var status;
          var data;
          var txt = x.responseText.replace(/^\s*|\s*$/g,"");
          status = txt.charAt(0);
          data = txt.substring(2);

          if (status == "") {
            // let's just assume this is a pre-response bailout and let it slide for now
          } else if (status == "-")
            alert("Error: " + data);
          else {
            if (target_id != "")
              document.getElementById(target_id).innerHTML = eval(data);
            else {
              try {
                var callback;
                var extra_data = false;
                if (typeof args[args.length-1] == "object") {
                  //如果是对象的话，必须有callback方法与extra_data变量
                  callback = args[args.length-1].callback;
                  extra_data = args[args.length-1].extra_data;
                } else {
                  callback = args[args.length-1];
                }
                callback(eval(data), extra_data);
              } catch (e) {
                sajax_debug("Caught error " + e + ": Could not eval " + data );
              }
            }
          }
        }
      }
      
      sajax_debug(func_name + " uri = " + uri + "/post = " + post_data);
      x.send(post_data);
      sajax_debug(func_name + " waiting..");
      delete x;
      return true;
    }