function oAjax( url ,callback)
{
    try{
        this.HttpRequest = null;
        this.Debug  = false;
        this.Url = url;
        this.ContentType = "text/xml";
        this.HttpRequest = this.createXMLHttpRequest();

        if ( this.HttpRequest == null )
        {
            this._debug("XMLHttpRequest create failure!");
            return;
        }

        var xhReq = this.HttpRequest;
        xhReq.onreadystatechange = function (){
            oAjax._OnReadyStateChange( xhReq,callback );
        }

    } catch(e){
       this._debug( "unknow err: " + e.message );
    }
}

/*
 * Get URL resource
 */
oAjax.prototype.Get = function() {

    this.SetContentType( "text/html" );
    this._get();
}

/*
 * Post data to the server
 */
oAjax.prototype.Post = function( arrKey, arrValue ) {

    var data = '';
    this.SetContentType( "application/x-www-form-urlencoded" );
    for( i = 0; i < arrKey.length; i ++)
    {
        data += "&" + escape(arrKey[i]) + "=" + escape(arrValue[i]);
		//data += "&" + arrKey[i] + "=" + arrValue[i];
    }
	//document.write(data);
    data = data.replace(/^&/g, "");
    this._post(data);
}

/*
 * Initialization for oAjax class
 */
oAjax.prototype.Init = function() {
    // initialization
}

/*
 * Change URL for Request
 */
oAjax.prototype.SetUrl = function( url ) {
    this.Url = url;
}

/*
 * Set content type for HTTP header before sending Request
 */
oAjax.prototype.SetContentType = function( type ) {
    this.ContentType = type;
}

oAjax.prototype.createXMLHttpRequest = function() {

    try { return new ActiveXObject("Msxml2.XMLHTTP");    } catch(e) {}
    try { return new ActiveXObject("Microsoft.XMLHTTP"); } catch(e) {}
    try { return new XMLHttpRequest();                   } catch(e) {}
    return null;
}

/*
 * Debug information for testing
 */
oAjax.prototype._debug = function(message) {

    if ( this.Debug )
    {
        alert(message);
    }
}

/*
 * Process message and data from server
 */
oAjax._OnReadyStateChange = function( xreq, callback ){
    if ( xreq == null )
    {
        return;    }

    /*Status is completed, then process result */
    if ( xreq.readyState == 4)
    {
        // OK
        if ( xreq.status == 200 )
        {
//			alert(xreq.responseText);
          	callback (this.ArrayValue(xreq.responseXML) );
        }else{
			alert('服务器端错误！');
			alert(xreq.responseText);
			document.write (xreq.responseText);
		}
    } else {
        // Others
//			alert(xreq.readyState);
    }
}

oAjax.prototype._SendRequest = function(HttpMethod, data){

    this._debug( 'Send Request ' + HttpMethod + data );

    if ( this.HttpRequest != null )
    {
        this.HttpRequest.open(HttpMethod, this.Url, true);

        if ( this.ContentType != null )
        {
            //  <FORM> MIME type: application/x-www-form-urlencoded
            this.HttpRequest.setRequestHeader("Content-Type", this.ContentType);
        }
        this.HttpRequest.send(data);
        return true;
    }
    return false;
}

/* Send GET Request to server */
oAjax.prototype._get = function () {

    this._debug( 'GET' );
    return this._SendRequest("GET", null);
}

/* Send POST Request and data to server */
oAjax.prototype._post = function (data) {

    this._debug( 'POST' );
    return this._SendRequest("POST", data);
}

oAjax.ArrayValue = function ( xmlobj ) {
    var array = new Array();
    var i = 0;
    var response = xmlobj.getElementsByTagName('Response')[0];
	var element = response.firstChild;
	array[i] = element.firstChild.nodeValue;
	while ( element = element.nextSibling )
	{
		i ++;
		array[i] = element.firstChild.nodeValue;
		}
	return array;
}