<script>
var fs=1
var direction="right"
function rollertext(whichone){
var thetext=whichone
for (i=0;i<thetext.length;i++){
document.write(thetext.charAt(i).fontsize(fs))

if (fs<7&&direction=="right")
fs++
else if (fs==7){
direction="left"
fs--
}
else if (fs==1){
direction="right"//osw
fs++
}
else if (fs>1&&direction=="left")
fs--

}
}

rollertext("Прикольный текст, неправда ли? Замени своим!")
</script>