append site overlay DIV

Overlays entire site with a black tint, disabling all links and bringing into focus anything above it.

$(function() {

   var docHeight = $(document).height();

   $(\"body\").append(\"
\"); $(\"#overlay\") .height(docHeight) .css({ 'opacity' : 0.4, 'position': 'absolute', 'top': 0, 'left': 0, 'background-color': 'black', 'width': '100%', 'z-index': 5000 }); });