最简单的ajax应用

var  http_request  =   false ;  
  function  send_request(url)  ... {  
        http_request = false;   
        //Init XMLHttpRequest object   
        if(window.XMLHttpRequest) ...{ //Mozilla    
            http_request = new XMLHttpRequest();   
            if (http_request.overrideMimeType) ...{//set MiME   
                http_request.overrideMimeType('text/xml');   
            }   
        }   
        else if (window.ActiveXObject) ...{ // IE
            try ...{   
                http_request = new ActiveXObject("Msxml2.XMLHTTP");   
            } catch (e) ...{   
                try ...{   
                    http_request = new ActiveXObject("Microsoft.XMLHTTP");   
                } catch (e) ...{}   
            }   
        }   
        if (!http_request) ...{ // excetion  
            window.alert("Can't create XMLHttpRequest object");   
            return false;   
        }   
        http_request.onreadystatechange = processRequest;   
        http_request.open("GET", url, true);   
        http_request.send(null);   
    }    

 

function  processRequest()  ... { 
        if (http_request.readyState == 4) ...{    
            if (http_request.status == 200) ...{   
                var returnStr = http_request.responseText;
                store.load(...{params:...{start:0, limit:25}});
            }   
        } else ...{
                Ext.MessageBox.alert("Server Error,can not connect to the server");   
        }   
    }   

 

 

使用时,调用send_request(url)方法,,url为需要调用的页面,在processRequest中对返回结果进行处理