/**
 * Change style for div box of current news detail.
 * @param  string    div box id
 **/
function newsDisplayDetail(id) {
	if(document.getElementById('overlay').style.display == 'none') {
		document.getElementById('overlay').style.display = '';
		document.getElementById(id).style.display = '';
		opacity(id + '_item',0,100,1000);
	} else {
		opacity(id + '_item',100,0,1000);
		window.setTimeout('newsDisplayDetailClose("' + id + '")',1200);
	}
}
function newsDisplayDetailClose(id) {
	document.getElementById('overlay').style.display = 'none';
	document.getElementById(id).style.display = 'none';
}
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 == 0) {
		opacity(id, 0, 100, millisec);
	} else {
		opacity(id, 100, 0, millisec);
	}
}