layer n fecha no firefox

tenho este codigo, pra fechar uma layer, ele funciona no IE mais n funciona no firefox alguem pode me ajudar?grato!<script language="javascript">var dragswitch=0var nsxvar nsyvar nstempvar dragapproved=falsefunction drag_dropie(){if (dragapproved==true){document.all.showimage.style.pixelLeft=tempx+event.clientX-iexdocument.all.showimage.style.pixelTop=tempy+event.clientY-ieyreturn false}}//function drag_dropie(){if (dragapproved==true){document.all.showimage.style.pixelLeft=tempx+event.clientX-iexdocument.all.showimage.style.pixelTop=tempy+event.clientY-ieyreturn false}}function stopns(){temp.releaseEvents(Event.MOUSEMOVE)}function dragns(e){if (dragswitch==1){temp.moveBy(e.x-nsx,e.y-nsy)return false}}function gons(e){temp.captureEvents(Event.MOUSEMOVE)nsx=e.xnsy=e.y}//function initializedragie(){iex=event.clientXiey=event.clientYtempx=showimage.style.pixelLefttempy=showimage.style.pixelTopdragapproved=truedocument.onmousemove=drag_dropie}if (document.all){document.onmouseup=new Function("dragapproved=false")}function hidebox(){if (document.all)showimage.style.visibility="hidden"else if (document.layers)document.showimage.visibility="hide"}</script></body></html>