function movetop(){
if (laytexto.style.pixelTop<0)
laytexto.style.pixelTop+=6
toptime=setTimeout("movetop()",50)
}

function movebot(){
if (laytexto.style.pixelTop>(laybase.offsetHeight-laytexto.offsetHeight))
laytexto.style.pixelTop-=6
bottime=setTimeout("movebot()",50)
}