window.onerror = null;

var topMargin = 0;
var slideTime = 500;
var ns6 = (!document.all && document.getElementById);
var ie4 = (document.all);
var ns4 = (document.layers);

function layerObject(id,left) {
	if (ns6) {
	this.obj = document.getElementById(id).style;
	this.obj.left = left;
	return this.obj;
	}
	else if(ie4) {
	this.obj = document.all[id].style;
	this.obj.left = left;
	return this.obj;
	}
	else if(ns4) {
	this.obj = document.layers[id];
	this.obj.left = left;
	return this.obj;
	   }
}
function layerSetup() {
	floatLyr = new layerObject('floatLayer', pageWidth * .5);
	window.setInterval("main()", 10)
}
function floatObject() {
	if (ns4 || ns6) {
	findHt = window.innerHeight;
	} else if(ie4) {
	findHt = document.body.clientHeight;
	   }
} 
function main() {
	if (ns4) {
	this.currentY = document.layers["floatLayer"].top;
	this.scrollTop = window.pageYOffset;
	mainTrigger();
}
	else if(ns6) {
	this.currentY = parseInt(document.getElementById('floatLayer').style.top);
	this.scrollTop = scrollY;
	mainTrigger();
	} else if(ie4) {
	this.currentY = floatLayer.style.pixelTop;
	this.scrollTop = document.body.scrollTop;
	mainTrigger();
	}
}
function mainTrigger() {
	var newTargetY = this.scrollTop + this.topMargin;
	if ( this.currentY != newTargetY ) {
	if ( newTargetY != this.targetY ) {
	this.targetY = newTargetY;
	floatStart();
	}
	animator();
	}
}
function floatStart() {
	var now = new Date();
	this.A = this.targetY - this.currentY;
	this.B = Math.PI / ( 2 * this.slideTime );
	this.C = now.getTime();
	if (Math.abs(this.A) > this.findHt) {
	this.D = this.A > 0 ? this.targetY - this.findHt : this.targetY + this.findHt;
	this.A = this.A > 0 ? this.findHt : -this.findHt;
	}
	else {
	this.D = this.currentY;
	}
}
function animator() {
	var now = new Date();
	var newY = this.A * Math.sin( this.B * ( now.getTime() - this.C ) ) + this.D;
	newY = Math.round(newY);
	if (( this.A > 0 && newY > this.currentY ) || ( this.A < 0 && newY < this.currentY )) {
	if ( ie4 )document.all.floatLayer.style.pixelTop = newY;
	if ( ns4 )document.layers["floatLayer"].top = newY;
	if ( ns6 )document.getElementById('floatLayer').style.top = newY + "px";
   }
}
function start() {
	if(ns6||ns4) {
	pageWidth = innerWidth;
	pageHeight = innerHeight;
	layerSetup();
	floatObject();
}
else if(ie4) {
	pageWidth = document.body.clientWidth;
	pageHeight = document.body.clientHeight;
	layerSetup();
	floatObject();
   }
}