function ietruebody(){
return (document.compatMode && document.compatMode!="BackCompat" && !window.opera)? document.documentElement : document.body
}

function centerLay(box, type){
var firefox=document.getElementById&&!document.all
var posX=firefox? pageXOffset+window.innerWidth/2-box.offsetWidth/2 : ietruebody().scrollLeft+ietruebody().clientWidth/2-box.offsetWidth/2
var posY=firefox? pageYOffset+window.innerHeight/2-box.offsetHeight/2 : ietruebody().scrollTop+ietruebody().clientHeight/2-box.offsetHeight/2
if (type=="left")
return posX
else
return posY
}

function overlay(curobj, subobj){
if (document.getElementById){
var subobj=document.getElementById(subobj)
subobj.style.left=centerLay(subobj, "left")+"px"
subobj.style.top=centerLay(subobj, "top")+"px"
subobj.style.visibility="visible"
return false
}
else
return true
}

function overlayclose(subobj){
document.getElementById(subobj).style.visibility="hidden"
}