/*  Prototype JavaScript framework
 *  (c) 2009 Triq Media (info@triq.web.id)
 *  Prototype is not freely distributable, abide the Indonesia law.
 *  For details, see the Prototype web site: http://sanugrah.com/float.php
/*--------------------------------------------------------------------------*/

var IsBrowserIE = false;

// ---------------------------------------------------------------------------------------------------------------------------------------------------
// Solution variables
// ---------------------------------------------------------------------------------------------------------------------------------------------------
var activeXType;
var HttpXMLObj;

/*##############################################
#
# Function: isSupportedBrowser()
#
# Description: 
#		Determines if a browser supports the necessary technology 
#		to implement an AJAX (Asynchronous Javascript and XML) 
#		solution.
#	           
#*/
function isSupportedBrowser()
{
	// IE creates an XMLHttpRequest object differently from other browsers, thus, we need to do a check 
	// to handle the different ways of creating the XMLHttpRequest object. 
	//

	// Check to see if the XMLHTTPRequest object is supported by the non-IE browser
	if (window.XMLHttpRequest != null)
	{
		return true;
	}

	// Check if the platform is Windows and the version of IE supports AJAX.
	if (navigator.platform.toLowerCase() == 'win32' || navigator.platform.toLowerCase() == 'win64')
	{
		if (window.ActiveXObject != null)
		{
			// Get the browser's user agent. 
			var UserAgent = navigator.userAgent.toLowerCase();

			// Determine if the browser is Internet Explorer 5+, if so browser is supported
			if (parseInt(UserAgent.substring(UserAgent.indexOf('msie ') + 5 )) >= 5)
			{
				IsBrowserIE = true;
				return true;
			}
		}
	}

	// If we reach this part, it means that the browser does not support AJAX.
	return false;
}


/*##############################################
#
# Function: isPlatformWindows()
#
# Description: 
#		Determines if the current operating
#		system being used is Windows.
#	           
#*/
function isPlatformWindows()
{
	if ((navigator.platform.toLowerCase() == 'win32') || (navigator.platform.toLowerCase() == 'win64'))
	{
		return true;
	}
	
	return false;
}


/*##############################################
#
# Function: getNewHttpXmlObject()
#
# Description: 
#		Gets a new MSXML XMLHTTP object or a XML Http Request object
#	           
#*/
function getNewHttpXmlObject()
{	
	// Get object based on OS and browser type 
	if (isPlatformWindows() && IsBrowserIE)
	{		
		if (activeXType == null)
		{
			// List of all possible versions of the XMLHTTP object
			var HttpXmlProgIdCandidates = [
				'Microsoft.XMLHTTP',
				'MSXML2.XMLHTTP',
				'MSXML2.XMLHTTP.5.0',
				'MSXML2.XMLHTTP.4.0',
				'MSXML2.XMLHTTP.3.0'];

			// Iterate through each version and use the first one that works.
			for (var i = 0; i < HttpXmlProgIdCandidates.length; i++)
			{
				try
				{
					// Instantiate object
					HttpXMLObj = new ActiveXObject(HttpXmlProgIdCandidates[i]);
					activeXType = HttpXmlProgIdCandidates[i];

					// Return with success
					return true
				}
				catch (objException) {}
			}
		}
		else
		{
			// Use previously selected versions of the XMLHTTP object
			HttpXMLObj  = new ActiveXObject(activeXType);

			return true;
		}
	}
	else
	{
		// All non Windows/IE combinations
		try
		{
			// Instantiate object
			HttpXMLObj  = new XMLHttpRequest();				
			return (HttpXMLObj  != null);
		}
		catch (objException) {}
	}

	// Return false if we get here as we failed
	return false;
}


/*##############################################
#
# Function: makeDCCProxyCall()
#
# Description: 
#		Invokes an AJAX request.
#
# Parameters:
#		strPostPayload 		- The parameters we would like to submit along with the URL.
#		verb 			- Method verb ("GET" or "POST") 
#						Note: IE5 requires that the method verb POST be in uppercase to work on Https
#		proxy_url: 		- Location of where the GET or POST will be made.
#		readyStateFunction	- This is the name of the function that you wish to be called once the 
#					response has been received.
#	           
#*/
function makeDCCProxyCall(strPostPayload, verb, proxy_url, readyStateFunction) 
{
	// Get Http Xml object, if this fails exit function
	if (! getNewHttpXmlObject()) 
	{ 
		return; 
	}
	
	// Make post call to proxy (This should work in the same way for all supported OS/Browser combinations)
	// IE5 requires that the method verb POST be in uppercase to work on Https
	HttpXMLObj.onreadystatechange = readyStateFunction;
	HttpXMLObj.open(verb, proxy_url, true);
	HttpXMLObj.setRequestHeader('Content-Type', 'application/x-www-form-urlencoded');	
	HttpXMLObj.send(strPostPayload);	
}