IMG01 = "images/arrowr_on.gif"
IMG02 = "images/arrowr_off.gif"

IMG03 = "images/arrowl_on.gif"
IMG04 = "images/arrowl_off.gif"


function imgoverr(imgname){
     imgname.src = IMG01
}

function imgoutr(imgname){
     imgname.src = IMG02
}

function imgoverl(imgname){
     imgname.src = IMG03
}

function imgoutl(imgname){
     imgname.src = IMG04
}