block = false 	// this variable must be loaded immediately
				// or an error will occur onmouseover

ns4 = (document.layers)? true:false
ie4 = (document.all)? true:false

function init() {
	if (ns4) {
		block = document.blockDiv
		}
	else if (ie4) {
		block = blockDiv.style
	}
	else {
		block = false
	}
	block.left = 4
	block.xpos = parseInt(block.left)
	block.ypos = parseInt(block.top)
	block.up = false
	block.down = false
	ystop = 0
}

function stopOn(coordinate) {
	ystop = coordinate
	if (block != false) {
		slideTo()
	}
}

function slideTo() {

ystart = block.ypos
distance = ystop - ystart

	if (distance > 0) {
		if (block.ypos < ystop) {
			block.ypos += 5
			block.top = block.ypos
			setTimeout("slideTo()",30)
  		}
	}
	else {
		if (block.ypos > ystop) {
			block.ypos -= 5
			block.top = block.ypos
			setTimeout("slideTo()",30)
		}
	}
}