window.onerror = null;
var topMargin = 160;
var slideTime = 1200;
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('rocket', 0);
	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["rocket"].top;
		this.scrollTop = window.pageYOffset;
		mainTrigger();
	} else if(ns6) {
		this.currentY = parseInt(document.getElementById('rocket').style.top);
		this.scrollTop = scrollY;
		mainTrigger();
	} else if(ie4) {
		this.currentY = rocket.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.rocket.style.pixelTop = newY;
		if ( ns4 )document.layers["rocket"].top = newY;
		if ( ns6 )document.getElementById('rocket').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();
	}
}