function close_preview(){
	var preview=document.getElementById('preview');
	preview.className='hidepreview';
}


window.setTimeout(autoclose,1500);
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++; 
		}
	}
	window.setTimeout(close_preview,600);
}

function autoclose () {
	// Id of the element containing the image to fade-out
	var previewId = 'preview';
	
	// Do fade-out
	opacity(previewId, 100, 0, 500);
}

//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 + ")"; 
}