function floatButton () {
	if (document.all) {
		if(document.body.scrollTop>100){
			document.all.topButton.style.visibility = 'visible';
			document.all.topButton.style.pixelTop = document.body.scrollTop;
		}else{
			document.all.topButton.style.visibility = 'hidden';
		}
	}else if (document.layers) {
		if(window.pageYOffset>100){
			document.topButton.visibility = 'show';
			document.topButton.top = window.pageYOffset;
		}else{
			document.topButton.visibility = 'hide';
		}
	}else if (document.getElementById) {
		if(window.pageYOffset>100){
			document.getElementById('topButton').style.visibility = 'visible';
			document.getElementById('topButton').style.top = window.pageYOffset + 'px';   
		}else{
			document.getElementById('topButton').style.visibility = 'hidden';
		}
	}
}

if (document.all) window.onscroll = floatButton;
else setInterval ('floatButton()', 100);