一:Ajax思路:
1: send_request('sample1_2.jsp?username='+username);
2: http_request = new ActiveXObject("Msxml2.XMLHTTP");
3:http_request.onreadystatechange = processRequest;
4:http_request.open("GET", url, true);
http_request.send(null);
5:if (http_request.readyState == 4)
if (http_request.status == 200)
说明:alert(http_request.responseText);返回整个页面内容