function showAlertDiv(alertDiv) {
	document.body.appendChild(alertDiv);
	opacity('alertDiv', 0, 100, 500);
	
	setTimeout("destroyAlertDiv(document.getElementById('alertDiv'))", 5000);
}

function createAlertDiv(mesaj) {
	var olddiv = document.getElementById("alertDiv");	
	var alertDiv;
	var i;
	
	if(olddiv == null) {
		alertDiv = document.createElement("div");
		alertDiv.id = "alertDiv";
		alertDiv.className = "alertdiv";
		alertDiv.innerHTML = mesaj;

	
		showAlertDiv(alertDiv);
	} else {
		olddiv.innerHTML = mesaj;
	}
}

function destroyAlertDiv(olddiv) {
	if(olddiv) {
		opacity('alertDiv', 100, 0, 500);
	 	setTimeout(function() {
					 		if(document.getElementById("alertDiv").style.opacity <= 1)
					 			document.body.removeChild(olddiv);
						 	}, 501);
	}
}

function opacity(id, opacStart, opacEnd, millisec) {
	//speed for each frame
	var speed = Math.round(millisec / 100);
	var timer = 0;

	//determine the direction for the blending, if start and end are the same nothing happens
	if(opacStart > opacEnd) {
		for(i = opacStart; i >= opacEnd; i--) {
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	} else if(opacStart < opacEnd) {
		for(i = opacStart; i <= opacEnd; i++) {
			setTimeout("changeOpac(" + i + ",'" + id + "')",(timer * speed));
			timer++;
		}
	}
}

//change the opacity for different browsers
function changeOpac(opacity, id) {
	var object = document.getElementById(id).style;
	object.opacity = (opacity / 100);
	object.MozOpacity = (opacity / 100);
	object.KhtmlOpacity = (opacity / 100);
	object.filter = "alpha(opacity=" + opacity + ")";
}

function shiftOpacity(id, millisec) {
	//if an element is invisible, make it visible, else make it ivisible
	if(document.getElementById(id).style.opacity == 100) {
		opacity(id, 100, 0, millisec);
	} else {
		opacity(id, 0, 100, millisec);
	}
}