//-----------------------------------------------------
//
//	Mouse Banner
//
//	Displays a trail of letters following mouse cursor
//	Compatible with IE4+, Netscape 4 and Mozilla
//
//------------------------------------------------------

var nDots = 8;

if (isIE4&&document.all&&window.print)
	document.body.style.cssText="overflow-x:hidden;overflow-y:scroll"

var Xpos = 0;
var Ypos = 0;
var DELTAT = .01;
var SEGLEN = 10;
var SPRINGK =10;
var MASS = 1;
var GRAVITY = 40;
var RESISTANCE = 10;
var STOPVEL = 0.1;
var STOPACC = 0.1;
var DOTSIZE = 11;
var BOUNCE = 0.75;
var followmouse = true;
var dots = new Array();

// Simple Browser sniffer
var agt=navigator.userAgent.toLowerCase();
var isOP5=(agt.indexOf("opera") != -1)?true:false;
var isNS4 = (document.layers)?true:false;
var isNS6 = (!document.all&&document.getElementsByTagName&&!isOP5)?true:false;
var isIE4 = (document.all)?true:false;

function mousebannerInit()
{
    if (isOP5) {
    	// hides the welcome text from the user
    	for (i = 0; i < nDots; i++) {
        theobj = document.getElementById("dot"+i);
    		theobj.style.visibility = "hidden";
        }
    }
    else {
        var i = 0;
        for (i = 0; i < nDots; i++) {
            dots[i] = new dot(i);
        }
    
        if (!isNS4) {
        }
    
        for (i = 0; i < nDots; i++) {
            dots[i].obj.left = dots[i].X;
            dots[i].obj.top = dots[i].Y;
        }
    
        catchEvent();
    
        if (isNS4||isNS6) {
            startanimate();
        } else if (isIE4) {
            setTimeout("startanimate()", 2000);
        }
    }
}

function dot(i)
{
    this.X = Xpos;
    this.Y = Ypos;
    this.dx = 0;
    this.dy = 0;
    if (isNS4) {
        this.obj = eval("document.dot" + i);
    }
	else if (isIE4) {
        this.obj = eval("dot" + i + ".style");
    }
	else if (isNS6) {
		var theobj = document.getElementById("dot"+i);
		this.obj = theobj.style;
	}
	
}


function startanimate() {
    setInterval("animate()", 20);
}

function setInitPositions(dots)
{
    var startloc = document.all.tags("LI");
    var i = 0;
    for (i = 0; i < startloc.length && i < (nDots - 1); i++) {
        dots[i+1].X = startloc[i].offsetLeft
            startloc[i].offsetParent.offsetLeft - DOTSIZE;
        dots[i+1].Y = startloc[i].offsetTop +
            startloc[i].offsetParent.offsetTop + 2*DOTSIZE;
    }
    dots[0].X = dots[1].X;
    dots[0].Y = dots[1].Y - SEGLEN;
}

function MoveHandlerNS4(e)
{
    Xpos = e.pageX;
    Ypos = e.pageY;
    return true;
}

function MoveHandlerIE4() {
    Xpos = window.event.x + document.body.scrollLeft;
    Ypos = window.event.y + document.body.scrollTop;
}

function MoveHandlerOP5(e) {
	Xpos = e.screenX;
    Ypos = e.screenY;
	window.status=Xpos+","+Ypos;
    return true;
}

function catchEvent()
{
    if (isNS4) {
        document.captureEvents(Event.MOUSEMOVE);
        document.onMouseMove = MoveHandlerNS4;
    } else if (isIE4) {
        document.onmousemove = MoveHandlerIE4;
    } else if (isNS6) {
    	document.onmousemove = MoveHandlerNS4;
    }
}


function vec(X, Y)
{
    this.X = X;
    this.Y = Y;
}

function springForce(i, j, spring)
{
    var dx = (dots[i].X - dots[j].X);
    var dy = (dots[i].Y - dots[j].Y);
    var len = Math.sqrt(dx*dx + dy*dy);
    if (len > SEGLEN) {
        var springF = SPRINGK * (len - SEGLEN);
        spring.X += (dx / len) * springF;
        spring.Y += (dy / len) * springF;
    }
}


function animate() {
    var start = 0;
    if (followmouse) {
        dots[0].X = Xpos;
        dots[0].Y = Ypos;
        start = 1;
    }

    for (i = start ; i < nDots; i++ ) {

        var spring = new vec(0, 0);
        if (i > 0) {
            springForce(i-1, i, spring);
        }
        if (i < (nDots - 1)) {
            springForce(i+1, i, spring);
        }

        var resist = new vec(-dots[i].dx * RESISTANCE,
            -dots[i].dy * RESISTANCE);

        var accel = new vec((spring.X + resist.X)/ MASS + GRAVITY,
            (spring.Y + resist.Y)/ MASS);
        dots[i].dx += (DELTAT * accel.X);
        dots[i].dy += (DELTAT * accel.Y);

        if (Math.abs(dots[i].dx) < STOPVEL &&
            Math.abs(dots[i].dy) < STOPVEL &&
            Math.abs(accel.X) < STOPACC &&
            Math.abs(accel.Y) < STOPACC) {
            dots[i].dx = 0;
            dots[i].dy = 0;
        }

        dots[i].X += dots[i].dx;
        dots[i].Y += dots[i].dy;

        var height, width;
        if (isNS4||isNS6) {
            height = window.innerHeight + document.scrollTop;
            width = window.innerWidth + document.scrollLeft;
        } else if (isIE4) {
            height = document.body.clientHeight + document.body.scrollTop;
            width = document.body.clientWidth + document.body.scrollLeft;
		}
		

        if (dots[i].Y >=  height - DOTSIZE - 1) {
            if (dots[i].dy > 0) {
                dots[i].dy = BOUNCE * -dots[i].dy;
            }
            dots[i].Y = height - DOTSIZE - 1;
        }
        if (dots[i].X >= width - DOTSIZE) {
            if (dots[i].dx > 0) {
                dots[i].dx = BOUNCE * -dots[i].dx;
            }
            dots[i].X = width - DOTSIZE - 1;
        }
        if (dots[i].X < 0) {
            if (dots[i].dx < 0) {
                dots[i].dx = BOUNCE * -dots[i].dx;
            }
            dots[i].X = 0;
        }

        dots[i].obj.left = dots[i].X;
        dots[i].obj.top =  dots[i].Y;
    }
}