www.gusucode.com > JSP ExtJS图书管理系统源码程序 > JSP ExtJS图书管理系统/Ajax从入门到精通/8/Example/spell.js

    function $(str)
{
return document.getElementById(str);
}

/*
ajax使用说明：这个函数是对AJAX请求各个阶段函数的简单分离，
要实现Ajax的滚动条，可以实现AjaxLoading()方法
AjaxOK(str);是请求完成后执行的函数,str一般是http_request.responseText
*/
var http_request = false;
function ajaxRequest(url) {//注意这里的url包括参数
http_request = false;
if (window.XMLHttpRequest) { // Mozilla, Safari,...
   http_request = new XMLHttpRequest();
   if (http_request.overrideMimeType) {
    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) {
   alert('Giving up :( Cannot create an XMLHTTP instance');
   return false;
}
http_request.onreadystatechange = alertContents;
http_request.open('POST', url, true);
http_request.send(null);
}

function alertContents() {

if(http_request.readyState<4)
{
   AjaxLoading(); 
}
else if (http_request.readyState == 4) {
   if (http_request.status == 200) {
     str=http_request.responseText;//这个是返回的内容
            AjaxOK(str);
       alert(http_request.responseText);
   } else {
     alert('There was a problem with the request.');
   }
}
}

function AjaxLoading()
{
$('load').innerHTML='请求加载中……';
}

function AjaxOK(str)
{
/*
$('load').innerHTML=str;
*/
obj=$('small');
obj.options.length=0;
var myArray=str.split('|');

for(var i=0;i<myArray.length;i++)
{
   var eq=myArray[i].indexOf('=');//这里找到=的位置
   var length=myArray[i].length;
   myLabel=myArray[i].substring(0,eq);
   myValue=myArray[i].substring(eq+1,length);
   obj.add(new Option(myLabel,myValue));
}
$('load').innerHTML='';
}

function getSmall()
{
var obj=$('big');
var index=obj.selectedIndex;
var url='http://localhost:8080/techLab/ajax/fenlei.jsp?big='+ obj.options[index].value;
ajaxRequest(url);
}

function getSmallValue()
{
var obj=$('small');
var index=obj.selectedIndex;
alert(obj.options[index].value);
}

function getSmallIndex()
{
var obj=$('big');
var url='http://localhost:8080/techLab/ajax/fenlei.jsp?big='+ obj.options[0].value;
ajaxRequest(url);
}