// convert all characters to lowercase to simplify testing
var agt=navigator.userAgent.toLowerCase();

// *** BROWSER VERSION ***
// Note: On IE5, these return 4, so use is_ie5up to detect IE5.
var is_major = parseInt(navigator.appVersion);
var is_minor = parseFloat(navigator.appVersion);

// Note: Opera and WebTV spoof Navigator.  We do strict client detection.
// If you want to allow spoofing, take out the tests for opera and webtv.
var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1)
			&& (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1)
			&& (agt.indexOf('webtv')==-1) && (agt.indexOf('hotjava')==-1));
var is_nav2 = (is_nav && (is_major == 2));
var is_nav3 = (is_nav && (is_major == 3));
var is_nav4 = (is_nav && (is_major == 4));
var is_nav4up = (is_nav && (is_major >= 4));
var is_navonly      = (is_nav && ((agt.indexOf(";nav") != -1) ||
					  (agt.indexOf("; nav") != -1)) );
var is_nav6 = (is_nav && (is_major == 5));
var is_nav6up = (is_nav && (is_major >= 5));
var is_gecko = (agt.indexOf('gecko') != -1);

var is_ie     = ((agt.indexOf("msie") != -1) && (agt.indexOf("opera") == -1));
var is_ie3    = (is_ie && (is_major < 4));
var is_ie4    = (is_ie && (is_major == 4) && (agt.indexOf("msie 4")!=-1) );
var is_ie4up  = (is_ie && (is_major >= 4));
var is_ie5    = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.0")!=-1) );
var is_ie5_5  = (is_ie && (is_major == 4) && (agt.indexOf("msie 5.5") !=-1));
var is_ie5up  = (is_ie && !is_ie3 && !is_ie4);
var is_ie5_5up =(is_ie && !is_ie3 && !is_ie4 && !is_ie5);
var is_ie6    = (is_ie && (is_major == 4) && (agt.indexOf("msie 6.")!=-1) );
var is_ie6up  = (is_ie && !is_ie3 && !is_ie4 && !is_ie5 && !is_ie5_5);

var destUrl;
var hInterval = null;
var iTimerCount = 0;
var STEP_INTERVAL = 100;
var STEP_COUNT = 3;
var STEP_MAX = STEP_INTERVAL*STEP_COUNT;

function animatePage()
{
	if ( iTimerCount > STEP_MAX ) {
		window.clearInterval( hInterval );
		document.location = destUrl;
		hInterval = null;
		iTimerCount = 0;
	} else {
		iStep = 1 + Math.floor( iTimerCount / STEP_INTERVAL );
		document.all["book"].style.backgroundImage = "url(\"images/book_anim" + iStep + ".gif\")";
		iTimerCount += 20;
	}
}

function goToPage( url )
{
	if ( hInterval == null ) {
		// remove text from the page first
		text = document.getElementById("storytext"); 
		if ( text ) {
			text.style.display = "none";
		}

		destUrl = url;
		hInterval = window.setInterval( "animatePage()", 20 );
	}
}

function setHandCursor( obj )
{
	if ( obj.style ) {
		if ( is_ie6up || is_gecko ) {
			obj.style.cursor = "pointer";
		} else {
			obj.style.cursor = "hand";
		}
	}
}