vB 中的 AJAX 应用类

我们只是借鉴它的程序思想，不算是侵权吧？

代码:

// #############################################################################
// vB_AJAX_Handler
// #############################################################################

/**
* XML Sender Class
*
* @param	boolean	Should connections be asyncronous?
*/
function vB_AJAX_Handler(async)
{
	/**
	* Should connections be asynchronous?
	*
	* @var	boolean
	*/
	this.async = async ? true : false;
}

// =============================================================================
// vB_AJAX_Handler methods

/**
* Initializes the XML handler
*
* @return	boolean	True if handler created OK
*/
vB_AJAX_Handler.prototype.init = function()
{
	try
	{
		this.handler = new XMLHttpRequest();
		return (this.handler.setRequestHeader ? true : false);
	}
	catch(e)
	{
		try
		{
			this.handler = eval("new A" + "ctiv" + "eX" + "Ob" + "ject('Micr" + "osoft.XM" + "LHTTP');");
			return true;
		}
		catch(e)
		{
			return false;
		}
	}
}

/**
* Detects if the browser is fully compatible
*
* @return	boolean
*/
vB_AJAX_Handler.prototype.is_compatible = function()
{
	if (is_ie && !is_ie4) { return true; }
	else if (XMLHttpRequest)
	{
		try { return XMLHttpRequest.prototype.setRequestHeader ? true : false; }
		catch(e)
		{
			try { var tester = new XMLHttpRequest(); return tester.setRequestHeader ? true : false; }
			catch(e) { return false; }
		}
	}
	else { return false; }
}

/**
* Checks if the system is ready
*
* @return	boolean	False if ready
*/
vB_AJAX_Handler.prototype.not_ready = function()
{
	return (this.handler.readyState && (this.handler.readyState < 4));
}

/**
* OnReadyStateChange event handler
*
* @param	function
*/
vB_AJAX_Handler.prototype.onreadystatechange = function(event)
{
	if (!this.handler)
	{
		if  (!this.init())
		{
			return false;
		}
	}
	if (typeof event == 'function')
	{
		this.handler.onreadystatechange = event;
	}
	else
	{
		alert('XML Sender OnReadyState event is not a function');
	}
}

/**
* Sends data
*
* @param	string	Destination URL
* @param	string	Request Data
*
* @return	mixed	Return message
*/
vB_AJAX_Handler.prototype.send = function(desturl, datastream)
{
	if (!this.handler)
	{
		if (!this.init())
		{
			return false;
		}
	}
	if (!this.not_ready())
	{
		this.handler.open('POST', desturl, this.async);
		this.handler.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');
		this.handler.send(datastream + '&s=' + fetch_sessionhash());

		if (!this.async && this.handler.readyState == 4 && this.handler.status == 200)
		{
			return true;
		}
	}
	return false;
}

// we can check this variable to see if browser is AJAX compatible
var AJAX_Compatible = vB_AJAX_Handler.prototype.is_compatible();

具体应用在下面的 JS 文件中：

http://bbs.chinahtml.com/clientscript/vbulletin_ajax_threadslist.js