不错的ajax组件

function Xajax()
{
if (xajaxDebug) this.DebugMessage = function(text) { alert("Xajax Debug:/n " + text) };

this.workId = 'xajaxWork'+ new Date().getTime();
this.depth = 0;

//Get the XMLHttpRequest Object
this.getRequestObject = function()
{
if (xajaxDebug) this.DebugMessage("Initializing Request Object..");
var req;
try
{
req=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
try
{
req=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e2)
{
req=null;
}
}
if(!req && typeof XMLHttpRequest != "undefined")
req = new XMLHttpRequest();

if (xajaxDebug) {
if (!req) this.DebugMessage("Request Object Instantiation failed.");
}

return req;
}

// xajax.$() is shorthand for document.getElementById()
this.$ = function(sId)//$是什么?
{
return document.getElementById(sId);
}

// xajax.include(sFileName) dynamically includes an external javascript file
this.include = function(sFileName)
{
var objHead = document.getElementsByTagName('head');
var objScript = document.createElement('script');
objScript.type = 'text/javascript';
objScript.src = sFileName;
objHead[0].appendChild(objScript);
}

// xajax.addHandler adds an event handler to an element
this.addHandler = function(sElementId, sEvent, sFunctionName)
{
if (window.addEventListener)
{
//eval的含义?
eval("this.$('"+sElementId+"').addEventListener('"+sEvent+"',"+sFunctionName+",false);");
}
else
{
eval("this.$('"+sElementId+"').attachEvent('on"+sEvent+"',"+sFunctionName+",fal**);");
}
}

// *ajax.removeHandler removes an event handler from an element
this.removeHandler = function(sElementId, sEvent, sFunctionName)
{
if (window.addEventListener)
{
eval("this.$('"+sElementId+"').removeEventListener('"+sEvent+"',"+sFunctionName+",false);");
}
else
{
eval("this.$('"+sElementId+"').detachEvent('on"+sEvent+"',"+sFunctionName+",fal**);");
}
}

// *ajax.create creates a new child node under a parent
this.create = function(sParentId, sTag, sId)
{
var objParent = this.$(sParentId);
objElement = document.createElement(sTag);
objElement.setAttribute('id',sId);
objParent.appendChild(objElement);
}

// xajax.insert inserts a new node before another node
this.insert = function(sBeforeId, sTag, sId)
{
var objSibling = this.$(sBeforeId);
objElement = document.createElement(sTag);
objElement.setAttribute('id',sId);
objSibling.parentNode.insertBefore(objElement, objSibling);
}

this.getInput = function(sType, sName, sId)
{
var Obj;
if (sType == "radio" && !window.addEventListener)
{
alert('here');
Obj = document.createElement('<input type="radio" id="'+sId+'" name="'+sName+'">');
}
else
{
Obj = document.createElement('input');
Obj.setAttribute('type',sType);
Obj.setAttribute('name',sName);
Obj.setAttribute('id',sId);
}
return Obj;
}

// xajax.createInput creates a new input node under a parent
this.createInput = function(sParentId, sType, sName, sId)
{
var objParent = this.$(sParentId);
var objElement = this.getInput(sType, sName, sId);
objParent.appendChild(objElement);
}

// xajax.insertInput creates a new input node before another node
this.insertInput = function(sBeforeId, sType, sName, sId)
{
var objSibling = this.$(sBeforeId);
var objElement = this.getInput(sType, sName, sId);
objSibling.parentNode.insertBefore(objElement, objSibling);
}

// xajax.remove deletes an element
this.remove = function(sId)
{
objElement = this.$(sId);
if (objElement.parentNode && objElement.parentNode.removeChild)
{
objElement.parentNode.removeChild(objElement);
}
}

//xajax.replace searches for text in an attribute of an element and replaces it
//with a different text
this.replace = function(sId,sAttribute,sSearch,sReplace)
{
var bFunction = false;

eval("var txt=document.getElementById('"+sId+"')."+sAttribute);
if (typeof txt == "function")
        {
            txt = txt.toString();
            bFunction = true;
        }
if (txt.indexOf(sSearch)>-1)
{
var newTxt = '';
while (txt.indexOf(sSearch) > -1)
{
x = txt.indexOf(sSearch)+sSearch.length+1;
newTxt += txt.substr(0,x).replace(sSearch,sReplace);
txt = txt.substr(x,txt.length-x);
}
newTxt += txt;
if (bFunction)
{
eval("newTxt =" + newTxt);
eval('this.$("'+sId+'").'+sAttribute+'=newTxt;');
}
else if (this.willChange(sId,sAttribute,newTxt))
{
eval('this.$("'+sId+'").'+sAttribute+'=newTxt;');
}
}
}

// xajax.getFormValues() builds a query string XML message from the elements of a form object

function Xajax()
{
if (xajaxDebug) this.DebugMessage = function(text) { alert("Xajax Debug:/n " + text) };

this.workId = 'xajaxWork'+ new Date().getTime();
this.depth = 0;

//Get the XMLHttpRequest Object
this.getRequestObject = function()
{
if (xajaxDebug) this.DebugMessage("Initializing Request Object..");
var req;
try
{
req=new ActiveXObject("Msxml2.XMLHTTP");
}
catch (e)
{
try
{
req=new ActiveXObject("Microsoft.XMLHTTP");
}
catch (e2)
{
req=null;
}
}
if(!req && typeof XMLHttpRequest != "undefined")
req = new XMLHttpRequest();

if (xajaxDebug) {
if (!req) this.DebugMessage("Request Object Instantiation failed.");
}

return req;
}

// xajax.$() is shorthand for document.getElementById()
this.$ = function(sId)//$是什么?
{
return document.getElementById(sId);
}

// xajax.include(sFileName) dynamically includes an external javascript file
this.include = function(sFileName)
{
var objHead = document.getElementsByTagName('head');
var objScript = document.createElement('script');
objScript.type = 'text/javascript';
objScript.src = sFileName;
objHead[0].appendChild(objScript);
}

// xajax.addHandler adds an event handler to an element
this.addHandler = function(sElementId, sEvent, sFunctionName)
{
if (window.addEventListener)
{
//eval的含义?
eval("this.$('"+sElementId+"').addEventListener('"+sEvent+"',"+sFunctionName+",false);");
}
else
{
eval("this.$('"+sElementId+"').attachEvent('on"+sEvent+"',"+sFunctionName+",fal**);");
}
}

// *ajax.removeHandler removes an event handler from an element
this.removeHandler = function(sElementId, sEvent, sFunctionName)
{
if (window.addEventListener)
{
eval("this.$('"+sElementId+"').removeEventListener('"+sEvent+"',"+sFunctionName+",false);");
}
else
{
eval("this.$('"+sElementId+"').detachEvent('on"+sEvent+"',"+sFunctionName+",fal**);");
}
}

// *ajax.create creates a new child node under a parent
this.create = function(sParentId, sTag, sId)
{
var objParent = this.$(sParentId);
objElement = document.createElement(sTag);
objElement.setAttribute('id',sId);
objParent.appendChild(objElement);
}

// xajax.insert inserts a new node before another node
this.insert = function(sBeforeId, sTag, sId)
{
var objSibling = this.$(sBeforeId);
objElement = document.createElement(sTag);
objElement.setAttribute('id',sId);
objSibling.parentNode.insertBefore(objElement, objSibling);
}

this.getInput = function(sType, sName, sId)
{
var Obj;
if (sType == "radio" && !window.addEventListener)
{
alert('here');
Obj = document.createElement('<input type="radio" id="'+sId+'" name="'+sName+'">');
}
else
{
Obj = document.createElement('input');
Obj.setAttribute('type',sType);
Obj.setAttribute('name',sName);
Obj.setAttribute('id',sId);
}
return Obj;
}

// xajax.createInput creates a new input node under a parent
this.createInput = function(sParentId, sType, sName, sId)
{
var objParent = this.$(sParentId);
var objElement = this.getInput(sType, sName, sId);
objParent.appendChild(objElement);
}

// xajax.insertInput creates a new input node before another node
this.insertInput = function(sBeforeId, sType, sName, sId)
{
var objSibling = this.$(sBeforeId);
var objElement = this.getInput(sType, sName, sId);
objSibling.parentNode.insertBefore(objElement, objSibling);
}

// xajax.remove deletes an element
this.remove = function(sId)
{
objElement = this.$(sId);
if (objElement.parentNode && objElement.parentNode.removeChild)
{
objElement.parentNode.removeChild(objElement);
}
}

//xajax.replace searches for text in an attribute of an element and replaces it
//with a different text
this.replace = function(sId,sAttribute,sSearch,sReplace)
{
var bFunction = false;

eval("var txt=document.getElementById('"+sId+"')."+sAttribute);
if (typeof txt == "function")
        {
            txt = txt.toString();
            bFunction = true;
        }
if (txt.indexOf(sSearch)>-1)
{
var newTxt = '';
while (txt.indexOf(sSearch) > -1)
{
x = txt.indexOf(sSearch)+sSearch.length+1;
newTxt += txt.substr(0,x).replace(sSearch,sReplace);
txt = txt.substr(x,txt.length-x);
}
newTxt += txt;
if (bFunction)
{
eval("newTxt =" + newTxt);
eval('this.$("'+sId+'").'+sAttribute+'=newTxt;');
}
else if (this.willChange(sId,sAttribute,newTxt))
{
eval('this.$("'+sId+'").'+sAttribute+'=newTxt;');
}
}
}

// xajax.getFormValues() builds a query string XML message from the elements of a form object

 

this.call = function(sFunction, aArgs, sRequestType)
{
var i,r,postData;
if (document.body && xajaxWaitCursor)
document.body.style.cursor = 'wait';
if (xajaxStatusMessages == true) window.status = 'Sending Request...';
if (xajaxDebug) this.DebugMessage("Starting xajax...");
if (sRequestType == null) {
   var xajaxRequestType = xajaxDefinedPost;
}
else {
var xajaxRequestType = sRequestType;
}
var uri = xajaxRequestUri;
var value;
switch(xajaxRequestType)
{
ca** *ajaxDefinedGet:{
var uriGet = uri.indexOf("?")==-1?"?xajax="+encodeURIComponent(sFunction):"&xajax="+encodeURIComponent(sFunction);
for (i = 0; i<aArgs.length; i++)
{
value = aArgs[i];
if (typeof(value)=="object")
value = this.objectToXML(value);
uriGet += "&xajaxargs[]="+encodeURIComponent(value);
}
uriGet += "&xajaxr=" + new Date().getTime();
uri += uriGet;
postData = null;
} break;
ca** *ajaxDefinedPost:{
postData = "xajax="+encodeURIComponent(sFunction);
postData += "&xajaxr="+new Date().getTime();
for (i = 0; i <aArgs.length; i++)
{
value = aArgs[i];
if (typeof(value)=="object")
value = this.objectToXML(value);
postData = postData+"&xajaxargs[]="+encodeURIComponent(value);
}
} break;
default:
alert("Illegal request type: " + xajaxRequestType); return false; break;
}
r = this.getRequestObject();
r.open(xajaxRequestType==xajaxDefinedGet?"GET":"POST", uri, true);
if (xajaxRequestType == xajaxDefinedPost)
{
try
{
r.setRequestHeader("Method", "POST " + uri + " HTTP/1.1");
r.setRequestHeader("Content-Type", "application/x-www-form-urlencoded; charset=" + xajaxCharEncoding);
}
catch(e)
{
alert("Your browser does not appear to  support asynchronous requests using POST.");
return false;
}
}
r.onreadystatechange = function()
{
if (r.readyState != 4)
return;

if (r.status==200)
{
if (xajaxDebug && r.responseText.length < 1000) xajax.DebugMessage("Received:/n" + r.responseText);
else if (xajaxDebug) xajax.DebugMessage("Received:/n" + r.responseText.substr(0,1000)+".../n[long response]/n...</xajax>");
if (r.respon***ML)
xajax.processResponse(r.respon***ML);
else {
alert("Error: the XML response that was returned from the server is invalid.");
document.body.style.cursor = 'default';
if (xajaxStatusMessages == true) window.status = 'Invalid XML response error';
}
}

delete r;
}
if (xajaxDebug) this.DebugMessage("Calling "+sFunction +" uri="+uri+" (post:"+ postData +")");
r.send(postData);
if (xajaxStatusMessages == true) window.status = 'Waiting for data...';
delete r;
return true;
}

// Tests if the new Data is the same as the extant data
this.willChange = function(element, attribute, newData)
{
if (!document.body)
{
return true;
}
var oldData;
if (attribute == "innerHTML")
{
tmpXajax = this.$(this.workId);
if (tmpXajax == null)
{
tmpXajax = document.createElement("div");
tmpXajax.setAttribute('id',this.workId);
tmpXajax.style.display = "none";
tmpXajax.style.visibility = "hidden";
document.body.appendChild(tmpXajax);
}
tmpXajax.innerHTML = newData;
newData = tmpXajax.innerHTML;
tmpXajax.innerHTML = '';
}
eval("oldData=document.getElementById('"+element+"')."+attribute);
if (newData != oldData)
return true;

return false;
}

//Process XML xajaxResponses returned from the request
this.processResponse = function(xml)
{
if (xajaxStatusMessages == true) window.status = 'Processing...';
var tmpXajax = null;
xml = xml.documentElement;
if (xml == null) {
alert("Error: the XML response that was returned from the server cannot be processed.");
document.body.style.cursor = 'default';
if (xajaxStatusMessages == true) window.status = 'XML response processing error';
return;
}
for (i=0; i<xml.childNodes.length; i++)
{
if (xml.childNodes[i].nodeName == "cmd")
{
var cmd;
var id;
var property;
var data;
var search;
var type;
var before;

for (j=0; j<xml.childNodes[i].attributes.length; j++)
{
if (xml.childNodes[i].attributes[j].name == "n")
{
cmd = xml.childNodes[i].attributes[j].value;
}
if (xml.childNodes[i].attributes[j].name == "t")
{
id = xml.childNodes[i].attributes[j].value;
}
if (xml.childNodes[i].attributes[j].name == "p")
{
property = xml.childNodes[i].attributes[j].value;
}
if (xml.childNodes[i].attributes[j].name == "c")
{
type = xml.childNodes[i].attributes[j].value;
}
}
if (xml.childNodes[i].childNodes.length > 1)
{
for (j=0; j<xml.childNodes[i].childNodes.length; j++)
{
if (xml.childNodes[i].childNodes[j].nodeName == "s")
{
if (xml.childNodes[i].childNodes[j].firstChild)
search = xml.childNodes[i].childNodes[j].firstChild.nodeValue;
}
if (xml.childNodes[i].childNodes[j].nodeName == "r")
{
if (xml.childNodes[i].childNodes[j].firstChild)
data = xml.childNodes[i].childNodes[j].firstChild.data;
}
}
}
else if (xml.childNodes[i].firstChild)
data = xml.childNodes[i].firstChild.nodeValue;
else
data = "";

var objElement = this.$(id);
try
{
if (cmd=="al")
{
alert(data);
}
if (cmd=="js")
{
eval(data);
}
if (cmd=="in")
{
this.include(data);
}
if (cmd=="as")
{
if (this.willChange(id,property,data))
{
eval("objElement."+property+"=data;");
}
}
if (cmd=="ap")
{
eval("objElement."+property+"+=data;");
}
if (cm*=="**")
{
eval("objElement."+property+"=data+objElement."+property);
}
if (cmd=="rp")
{
this.replace(id,property,search,data)
}
if (cmd=="rm")
{
this.remove(id);
}
if (cmd=="ce")
{
this.create(id,data,property);
}
if (cmd=="ie")
{
this.insert(id,data,property);
}
if (cmd=="ci")
{
this.createInput(id,type,data,property);
}
if (cmd=="ii")
{
this.insertInput(id,type,data,property);
}
if (cmd=="ev")
{
eval("this.$('"+id+"')."+property+"= function(){"+data+";}");
}
if (cmd=="ah")
{
this.addHandler(id, property, data);
}
if (cmd=="rh")
{
this.removeHandler(id, property, data);
}
}
catch(e)
{
alert(e);
}
delete objElement;
delete cmd;
delete id;
delete property;
delete search;
delete data;
delete type;
delete before;
}
}
delete xml;
document.body.style.cursor = 'default';
if (xajaxStatusMessages == true) window.status = 'Done';
}
}

var xajax = new Xajax();