web.xml中load-on-startup标签的含义

function openLink(o){
var XHR,
config = (typeof o === 'object' && o!=null)?o : {},
scope = config.scope||window,
method = config.method||'GET',
cb = typeof config.callback === 'function' ? config.callback : function(){},
url = config.url,
params = config.params||{},
p = null,
addURLParam = function(url,key,value){
url += (url.indexOf('?') == -1 ? '?' : '&');
url += encodeURIComponent(key) + '=' + encodeURIComponent(value);
return url;
},
timeout = 30000;//30s

if(typeof url !== 'string'){
throw new Error('配置的请求地址错误!');
}

if(typeof XMLHttpRequest != 'undefined'){
XHR = new XMLHttpRequest();
}else if(typeof ActiveXObject != 'undefined'){
var versions = ['MSXML2.XMLHTTP.3.0','Msxml2.XMLHTTP.6.0','MSXML2.XMLHTTP','Microsoft.XMLHTTP'];
for(var i=0,len=versions.length;i<len;i++){
try{
XHR = new ActiveXObject(versions[i]);
break;
}catch(ex){

}
}
}else{
throw new Error('您的浏览器不能创建XHR对象!');
}

var t = setTimeout(function(){
XHR.abort();
throw new Error('timeout!');
},timeout);

XHR.onreadystatechange = function(){
if(XHR.readyState == 4){
if((XHR.status >= 200 && XHR.status < 300) || XHR.status == 304){
//success
//XHR.responseText
clearTimeout(t);
cb.call(scope,XHR.responseText);
}else{
//exception
throw new Error('Request is unsuccessfull: '+ XHR.status);
}
}
}
if(method.toUpperCase() == 'GET'){
for(var f in params){
url = addURLParam(url,f,params[f]);
}
}else if(method.toUpperCase() == 'POST'){
var a = [];
for(var f in params){
a.push(f+'='+encodeURIComponent(params[f]));
}
p = a.join('&');
}

XHR.open(method,url,true);
XHR.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8');
XHR.send(p);
}

<script type="text/javascript">
openLink({
method : 'post',
url : 'data/test.do',
params : {e:'中文abc123',r:5},
callback : function(responseText){
var o = eval('('+responseText+')');
alert(o.success);
}
});
</script>