html - Create iframe with javascript appending to a div

Question

I want to load/append the iframe into a div with regular javascript. I can do this with JQuery without a problem, but I dont want to include the js file. I keep getting the error 'document.getElementById("ad54")' (or whatever id I assign the div). I have the following code:

var link = "http://www.google.com"
var iframe = document.createElement('iframe');
iframe.frameBorder=0;
iframe.width="300px";
iframe.height="250px";
iframe.id="randomid";
iframe.setAttribute("src", link);
document.getElementById("ad54").appendChild(iframe);

<div id="ad54"></div>

Answer 1

You should write this inside window.onload like

window.onload = function(){
   var link = "http://www.quirksmode.org/iframetest2.html"
var iframe = document.createElement('iframe');
iframe.frameBorder=0;
iframe.width="300px";
iframe.height="250px";
iframe.id="randomid";
iframe.setAttribute("src", link);
document.getElementById("ad54").appendChild(iframe);

}