Someone

   var blanketId = "pageBlanket";
   var blanket = document.createElement("div");

    blanket.id = blanketId;
    blanket.name = blanketId;
    blanket.style.position = "absolute";
    blanket.style.width = "100%";
    blanket.style.height = "100%";
    blanket.style.filter = "alpha(opacity=55)";
 //blanket.style.backgroundColor = fadeColor;
 //blanket.style.visibility = "hidden";
    document.body.appendChild(blanket);