Hello,

As per what I understood you must use something which will get the object directly. Below are the 3 ways to do so.

Code:
// Way 1

function $(id) { return document.getElementById(id); }
function show() { $("tvframe").style.display=""; }
function hide() { $("tvframe").style.display="none"; }
Code:
// Way 2

function show() { document.getElementById("tvframe").style.display=""; }
function hide() { document.getElementById("tvframe").style.display="none"; }
Code:
// Way 3

document.write("<script src='use_prototype_js.js'></script>");
// Paste the URL for Prototype JS
 function show() { $("tvframe").style.display=""; }
 function hide() { $("tvframe").style.display="none"; }
Regards