var asyn_imported = 0;
var asyn_isIE =  (window.navigator.appName.toLowerCase().indexOf("microsoft") > -1) ;
var asyn_srcs = new Array();
var asyn_reportErrors = new Array();
var asyn_reportErrorCheckHandles = new Array();
var asyn_timeouts = new Array();
var asyn_timeoutRems = new Array();
var asyn_errors = new Array();
var asyn_rets = new Array();
var checkPeriod = 100;
var asyn_returnObject = new Array();
var asyn_returnXMLObject = new Array();
var asyn_errorMsgs = new Array();
var user_defined_error = -10240;
function asyn_setSuccess(asynReqId){
asyn_rets[asynReqId] = true;
}
function asyn_notifyReturn(asynReqId, obj){
var i = asynReqId;
var curSrc = asyn_srcs[i];
var curReportError = asyn_reportErrors[i];
var curTimeout = asyn_timeouts[i];
curReportError(asynReqId, curSrc, 0, obj);
}
function asyn_addReturnObject(asynReqId, obj){
asyn_setSuccess(asynReqId);
asyn_returnObject[asynReqId] = obj;
asyn_notifyReturn(asynReqId, obj);
}
function asyn_getReturnObject(asynReqId){
return asyn_returnObject[asynReqId];
}
function asyn_setError(asynReqId, errorCode, errorMsg){
asyn_rets[asynReqId] = true;
asyn_errors[asynReqId] = errorCode;
asyn_errorMsgs[asynReqId] = errorMsg;
}
//attrs: childNodes(Array),nodeName, nodeValue;innerText
//funs:  getAttribute()
function asyn_getReturnXMLObject(asynReqId){
return asyn_returnXMLObject[asynReqId];
}
function asyn_clearReturnObject(asynReqId){
 asyn_returnObject[asynReqId] = null;
} 
function asyn_addReturnXMLObject(asynReqId, xml){
asyn_setSuccess(asynReqId);
var root = null;
if (asyn_isIE){
var doc=new ActiveXObject("Microsoft.XMLDOM"); 
doc.async="false"; 
doc.loadXML(xml); 
if (doc.childNodes.length >= 1){
root = doc.childNodes[1];
}else{
root = doc.childNodes[0];
}
}	else{
var parser = new DOMParser();
var dom = parser.parseFromString(xml, "text/xml");
if (dom.documentElement.nodeName == "parsererror"){ // error when parsing
}
root = dom.documentElement;
}
asyn_returnXMLObject[asynReqId] = root;
asyn_notifyReturn(asynReqId, root);
/*	alert("root" + root.nodeName);
for (var i = 0; i <root.childNodes.length; i++){
alert("n:"+root.childNodes[i].nodeName);
alert("v:" + root.childNodes[i].nodeValue);
}
*/
}
function asyn_private_reportErrorProxy(asynReqId){
var i = asynReqId;
var curSrc = asyn_srcs[i];
var curReportError = asyn_reportErrors[i];
var curTimeout = asyn_timeouts[i];
asyn_timeoutRems[i] -= checkPeriod;
if (asyn_rets[i]){
clearInterval(asyn_reportErrorCheckHandles[i]);
if (asyn_errors[i] < 0){
curReportError(asynReqId, curSrc, asyn_errors[i], asyn_errorMsgs[asynReqId]);
}
}else if (asyn_timeoutRems[i] <= 0){
clearInterval(asyn_reportErrorCheckHandles[i]);
curReportError(asynReqId, curSrc, curTimeout, asyn_errorMsgs[asynReqId]);
}
}
function asyn_private_import(asynReqId){
var i = asynReqId;
var s = document.createElement("script");
var curSrc = asyn_srcs[i];
var curReportError = asyn_reportErrors[i];
var curTimeout = asyn_timeouts[i];
s.setAttribute("src", curSrc);
s.setAttribute("charset", "UTF-8");
//alert(curSrc);
var curreportErrorCheckHandle = setInterval("asyn_private_reportErrorProxy(" + asynReqId+");", checkPeriod);
asyn_reportErrorCheckHandles[i] = curreportErrorCheckHandle;
document.body.appendChild(s);
}
//resultHandler --> function (asynReqId, jsSrc, timeoutOrErrorCode, resultObject);
function asyn_import(jsSrc, timeout, resultHandler){
asyn_imported++;
//var l = "<script src='" + jsSrc + "'>";
//var l = jsSrc;
//var curSrcVar = "asyn_src_"+asyn_imported;
//eval(curSrcVar + " = \"" + l + "\";");
//alert(curVar + "=" + l);
//document.writeln(l));
var ic = asyn_imported;
jsSrc += "edu_calis_asyn_asynReqId=" + ic;
asyn_srcs[ic] = jsSrc;
asyn_reportErrors[ic] = resultHandler;
asyn_timeouts[ic] = 	asyn_timeoutRems[ic] = timeout;
asyn_rets[ic] = false;
setTimeout("asyn_private_import(" + ic + ");", 0);
return ic;
}