function showPage(pagenum){
	var pagenumel = document.getElementById("pagenum");
	var selectHighlight = document.getElementById("pageselect" + pagenum);
	
	for (var i = 1; i <= num_pages; i++) {
		
		hideel = "story_page_" + i;
		if(document.getElementById(hideel)){
			if(document.getElementById(hideel).style.display == 'block'){
				document.getElementById(hideel).style.display = 'none';
			}
		}
		
		if(i == pagenum){
			if(i == num_pages)
				selectHighlight.className = "current last";
			else
				selectHighlight.className = "current";
		}
		else{
			if(i == num_pages)
				document.getElementById("pageselect" + i).className = "last";
			else
				document.getElementById("pageselect" + i).className = "";
		}
	}
	showel = "story_page_" + pagenum;
	changeOpac(0,showel);
	document.getElementById(showel).style.display = 'block';
	opacity(showel, 0, 100, 1000);
	pagenumel.innerHTML = "P&aacute;gina " + pagenum + " de " + num_pages;
}

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 + ")";
}