function doSomething(e) {

	var code = e.keyCode;

	if (pres_mode && code == 33 && page > 0) {
		jumpTo(--page);

		return false;
	} else if (pres_mode && code == 34 && page < slides) {
		jumpTo(++page);

		return false;
	} else if (e.charCode == 98) {
		var disp;

		if (pres_mode) {
			pres_mode = 0;
			disp = "block";
		} else {
			pres_mode = 1;
			disp = "none";
		}

		var notes = document.getElementsByTagName("note");
		for (var i=0; i<notes.length; i++) {
			notes.item(i).style.display = disp;
		}
		var el = document.getElementById("page0");
		for (var i = 1; el; i++) {
			el.style.display = disp;
			el = document.getElementById("page"+i);
		}
		if (pres_mode) {
			jumpTo(page);
		}

		return false;
	}
 else {
		alert("kc = "+e.keyCode+"\ncc="+e.charCode+"Page "+page+" slides "+slides);

	}

	return true;
}

function jumpTo(p) {
	var el = document.getElementById("page"+last_page);
	el.style.display = "none";

        pageId="page"+p;
	el = document.getElementById(pageId);
	el.style.display = "block";
        alert("Jumping to page "+p+" "+pageId);
	last_page = p;
}

window.onkeypress = doSomething;

var pres_mode = 0;
var page = 0;
var last_page = 0;