var blanket = document.getElementById("blanket");
var popup = document.getElementById("popup");
var wrapper = document.getElementById("wrapper");

function setFade(obj, level) {
   obj.style.MozOpacity = level / 100;
   obj.style.filter = "alpha(opacity=" + level + ")";
}

function show() {
   blanket.style.display = "block";
   popup.style.display = "block";

   wrapper.style.overflow = 'hidden';
   wrapper.style.height = browserHeight() + "px";

   setFade(blanket, 90);
   setFade(popup, 100);
}

function hide() {
   blanket.style.display = "none";
   popup.style.display = "none";
   wrapper.style.overflow = "visible";
   wrapper.style.height = "100%";
}

function browserHeight() {
   if(typeof(window.innerWidth) == 'number') {
      //Non-IE
      return window.innerHeight - 2;
   }
   else if(document.documentElement && (document.documentElement.clientHeight)) {
      //IE 6+ in 'standards compliant mode'
      return document.documentElement.clientHeight;
   }
   else if(document.body && (document.body.clientHeight)) {
      //IE 4 compatible
      return document.body.clientHeight;
   }
}