function btt_install( ) {
	if( !document.getElementsByTagName ) {
		return;
	}
	var a, i = 0;
	while(( a = document.getElementsByTagName( 'a' )[i++] )) {
		if( '#top' == a.getAttribute( 'href' )) {
			a.onclick = function() {
				backToTop();
				return false;
			}
		}
	}
}

function backToTop() {
	var x1 = x2 = x3 = 0;
	var y1 = y2 = y3 = 0;
	
	if( document.documentElement ) {
		x1 = document.documentElement.scrollLeft || 0;
		y1 = document.documentElement.scrollTop || 0;
	}
	if( document.body ) {
		x2 = document.body.scrollLeft || 0;
		y2 = document.body.scrollTop || 0;
	}
	x3 = window.scrollX || 0;
	y3 = window.scrollY || 0;
	var x = Math.max(x1, Math.max(x2, x3));
	var y = Math.max(y1, Math.max(y2, y3));
	window.scrollTo(Math.floor(x / 2), Math.floor(y / 2));
	if (x > 0 || y > 0) {
		window.setTimeout( "backToTop()",25 );
	}
	return false;
}