Screen colorDepth Property

var x = "Color Depth: " + screen.colorDepth;

if (screen.colorDepth <= 8)
  //simple blue background color for 8 bit screens
  document.body.style.background = "#0000FF"
else
  //fancy blue background color for modern screens
  document.body.style.background = "#87CEFA"

var txt = "";
txt += "<p>Total width/height: " + screen.width + "*" + screen.height + "</p>";
txt += "<p>Available width/height: " + screen.availWidth + "*" + screen.availHeight + "</p>";
txt += "<p>Color depth: " + screen.colorDepth + "</p>";
txt += "<p>Color resolution: " + screen.pixelDepth + "</p>";