// constants to define the title of the alert and button text.
var ALERT_TITLE = "Melding";
var ALERT_BUTTON_TEXT = "Ok";
var CONFIRM_OK_TEXT = "Ok"     
var CONFIRM_CANCEL_TEXT = "Annuleren"

var globaltxt = "";			//bij meerdere alerts achter elkaar, tekst samenvoegen in globaltxt
var mObj;

// over-ride the alert method only if this a newer browser.
// Older browser will see standard alerts
if(document.getElementById) {
	// niet voor IE6 gebruiken; deze toont 'normale' alertbox
	if (! (document.all && navigator.appVersion.lastIndexOf('MSIE 6.0') != -1) )  {

		window.alert = function(txt) {
			createCustomAlert(txt, false);	//alleen OK button
		}
	
		window.custom_confirm = function(txt, OKtext, Canceltext) {  //OK en CANCEL button
			return createCustomAlert(txt, true, OKtext, Canceltext)
		}
	}	
}

function createCustomAlert(txt, isConfirm, OKtext, Canceltext) {
	
	//bij confirms kunnen specifieke teksten ipv "OK" en "CANCEL" bedacht zijn	
	if (OKtext != null && OKtext != "undefined") CONFIRM_OK_TEXT = OKtext
	if (Canceltext != null && OKtext != "undefined") CONFIRM_CANCEL_TEXT = Canceltext
	
	if (globaltxt != "") globaltxt += "<br/><br/>"
	globaltxt += txt

	// shortcut reference to the document object
	d = document;

	// if the modalContainer object already exists in the DOM, bail out.
	// PS: uitgezet, want we willen juist wel meerdere alerts achter elkaar kunnen tonen
//	if(d.getElementById("modalContainer")) return;

	// create the modalContainer div as a child of the BODY element
	mObj = d.getElementsByTagName("body")[0].appendChild(d.createElement("div"));
	mObj.id = "modalContainer";
	 // make sure its as tall as it needs to be to overlay all the content on the page
	mObj.style.height = d.documentElement.scrollHeight + "px";

	// create the DIV that will be the alert 
	alertObj = mObj.appendChild(d.createElement("div"));
	alertObj.id = "alertBox";
	
	// MSIE doesnt treat position:fixed correctly, so this compensates for positioning the alert
	// --> IE7 doet het weer wel goed, dus hoeft niet meer, IE6 laten we standaard alert tonen 
	//	if(d.all && !window.opera) 
	//		alertObj.style.top = document.documentElement.scrollTop + "px";
	
	// center the alert box
	alertObj.style.left = (d.documentElement.scrollWidth - alertObj.offsetWidth)/2 + "px";

	// create an H1 element as the title bar
	h1 = alertObj.appendChild(d.createElement("h1"));
	h1.appendChild(d.createTextNode(ALERT_TITLE));

	// create a paragraph element to contain the txt argument
	msg = alertObj.appendChild(d.createElement("p"));
//	msg.appendChild(d.createTextNode(txt.replace(/\n/g, "<br>" ) ));
	msg.innerHTML = globaltxt.replace(/\n/g, "<br />" ) ;

	// create an anchor element to use as the confirmation button.
	// aangepast; kan naast alert ook een confirm box zijn; in dat geval OK en CANCEL button
	if (isConfirm) {
	
		btn = alertObj.appendChild(d.createElement("a")	)	
		btn.id = OKtext? "closeTextConfirmTrue" : "closeBtnConfirmTrue"
		btn.appendChild(d.createTextNode(CONFIRM_OK_TEXT));
		btn.href = "#";
		btn.onclick = function() { removeCustomAlert(); return true }
		
		btn2 = alertObj.appendChild(d.createElement("a"))
		btn2.id = Canceltext? "closeTextConfirmFalse" : "closeBtnConfirmFalse"
		btn2.appendChild(d.createTextNode	(CONFIRM_CANCEL_TEXT));
		btn2.href = "#"	
		btn2.onclick = function() { removeCustomAlert(); return false  }
		
	} else {
		
		btn = alertObj.appendChild(d.createElement("a"));
		btn.id = "closeBtn";
		btn.appendChild(d.createTextNode(ALERT_BUTTON_TEXT));
		btn.href = "#";
		// set up the onclick event to remove the alert when the anchor is clicked
		btn.onclick = function() { removeCustomAlert(); return false; }

		//zet focus op 'OK' button
		btn.focus()

	}

}

// removes the custom alert from the DOM
function removeCustomAlert() {
	
	document.getElementsByTagName("body")[0].removeChild(document.getElementById("modalContainer"));
	delete mObj;
	//als meerdere alert-objecten achter elkaar, dan met \u00E9\u00E9n klik allemaal weghalen
	globaltxt = "";
	if (document.getElementById("modalContainer")) removeCustomAlert();
}