/*
* ajax call to retrieve and possible execute code on response from server
*
*/
function doTask(params) {
	if (document.implementation && window.document.implementation.createDocument)
	{
		xmlDoc = document.implementation.createDocument("", "", null);
		xmlDoc.onload = doResponse;
	}
	else if (window.ActiveXObject)
	{
		xmlDoc = new ActiveXObject("Microsoft.XMLDOM");
		xmlDoc.onreadystatechange = function () {
			if (xmlDoc.readyState == 4) doResponse()
		};
	}
	else
	{
		return false;
	}
	d = new Date; // Generic - use to create unique url requests
	var rand = d.getTime();
	var url=document.location.protocol+'//'+document.location.host+'/alt/doTask.xml?rand='+rand+'&'+params;
	try{
		xmlDoc.load(url); // this is what we like to do
	} catch(e) { // if failed try using httprequest as a fallback - (e.g. Safari)
		try {
			req = new XMLHttpRequest();
		} catch(e) {
			req = false;
		}
		if(req) {
			req.onreadystatechange = processHttpRequest;
			req.open("GET", url, true);
			req.send("");
		}

	}

	return false;
}

/*
* some browsers require this extra step to catch the http reponse
*
*/
function processHttpRequest() {
	if (req.readyState == 4) {
		if (req.status == 200) {
			xmlDoc=req.responseXML;
			doResponse();
		}
	}
}

/*
* process the response from server to the doTask function,
*
*/
function doResponse() {
	var tasks = xmlDoc.getElementsByTagName('task');
	var cmd=null;

	for(var i=0;i<tasks.length;i++) {
		cmd=tasks[i].getElementsByTagName('cmd')[0];

		if (cmd.childNodes[0]) {
			switch(cmd.childNodes[0].nodeValue) {
				case 'replace': // replace the innerHTML of an element
					var id=tasks[i].getElementsByTagName('id')[0].childNodes[0].nodeValue;
					if (tasks[i].getElementsByTagName('content')[0].textContent) var content=tasks[i].getElementsByTagName('content')[0].textContent; //avoid FF 4096 char limit
					else var content=tasks[i].getElementsByTagName('content')[0].childNodes[0].nodeValue;
					if (id.length>0 && document.getElementById(id)) document.getElementById(id).innerHTML=content;
					break;
				case 'execute': // run some js
					var script=tasks[i].getElementsByTagName('script')[0].childNodes[0].nodeValue;
					eval(script);
					break;

			}
		}
	}
}

/*
* use JS to hide controls which are only required when JS is not enabled
* - do this by adding hideJS as a class to the css
*/
function hideElements() {
	if (document.styleSheets) {
		if (document.styleSheets[0].addRule) {    // IE
			document.styleSheets[0].addRule('.hideJS','display: none',0);
		} else {    // !IE
			document.styleSheets[0].insertRule('.hideJS {display: none}', 0);
		}
	}

}

/*
* Add the onload function to any other onload function
*/
function addLoadEvent(func) {
	var oldonload = window.onload;

	if (typeof window.onload != 'function') {
		window.onload = func;
	} else {
		window.onload = function() {
			oldonload();
			func();
		}
	}
}

addLoadEvent(hideElements);

// show the form wait box
function showWait(id) {
	if (document.getElementById(id)) {
		var el=document.getElementById(id);

		el.style.position='absolute';
		el.style.left='50%';
		el.style.top='50%';
		el.style.display='block';
		el.style.marginLeft="-" + parseInt(el.offsetWidth  / 2)+'px';
		el.style.marginTop ="-" + parseInt(el.offsetHeight / 2)+'px';
		// IE has a quirk which means we need to reload the animated gif to make it animate
		if (document.getElementById(id+'wImg')) setTimeout("document.getElementById('"+id+"wImg').src=document.getElementById('"+id+"wImg').src",20);
	}
}

function payOptions(issueNo, startMonth, startYear, pMethod) {
	switch(pMethod.toLowerCase()) {
		case 'invoice':
			//document.getElementById('ccoptions').style.display='none';
			//document.getElementById('invoiceoptions').style.display='block';
			break;
		default:
			document.getElementById('ccoptions').style.display='block';
			//document.getElementById('invoiceoptions').style.display='none';
			document.getElementById('issueno').disabled=issueNo;
			document.getElementById('startmonth').disabled=issueNo;
			document.getElementById('startyear').disabled=issueNo;
			break;
	}
}