AJAX显示数据动态刷新,面试题,俺不会AJAX,请各位帮忙解答一下 - Web 开发 / Ajax
做一个AJAX显示数据动态刷新的例子,后台可以用随机数产生数据,前台动态显示,1秒1次。
------解决方案--------------------一个Timer+微软的Ajax UpdatePanel就可以实现了
------解决方案--------------------setTimeout/setInterval轮询动态页
------解决方案--------------------javascript
1.1秒更新
var timerID = 0;
window.onload = function(){
GetRecentInfo();
timerID = window.setInterval("GetRecentInfo()",1000 );
}
2.创建提出请求
function GetRecentInfo()
{
  try{
 XMLhttpObject = new XMLHttpRequest();
  }catch(e){
 try{
  XMLhttpObject = new ActiveXObject("Msxml2.XMLHTTP");
 }catch(e){
  try{
   XMLhttpObject = new ActiveXObject("Microsoft.XMLHTTP");
  }
  catch(e){
   alert("XMLhttpObject error");
  }
 }
  }
  if(XMLhttpObject) {
 XMLhttpObject .onreadystatechange = DisplayInfo;入返回时处理函数名)
 XMLhttpObject .open("POST", "/servletname(写入servlet的配置名称)",true)
 XMLhttpObject .setRequestHeader("content-type","application/x-www-form-urlencoded;charset=UTF-8");		
 XMLhttpObject.send("pageid=jspname(写入response返回的叶面名);
  }
}
3.表示信息
function DisplayInfo()
{
  if((XMLhttpObject.readyState == 4 ) && (XMLhttpObject.status == 200)) {
  var csvdata = XMLhttpObject.responseText;
  var LF = String.fromCharCode(10);
   var lineData = csvdata.split(LF);
  if( lineData.length > 0 ) {
    document.getElementById("info").innerText = lineData[0];
  }else{
    document.getElementById("info").innerText = "取得失败";
  }
 }
}
------解决方案--------------------