Check for https with javascript

How?

[Easy_Coder]

How do you determine if a page is secured (ssl) with javascript?

[Easy_Coder]

Is there a better way to determine from an iframe if the parent window is secure? What I'm wanting to do is make sure that if the parent is https that the iframe loads under https too.

var loc = new String(window.parent.document.location);
if (loc.indexOf("https://")!= -1)
prefix = "https://";
else
prefix = "http://";

[Bernard Marx]

<edit>

prefix = parent.location.protocol + '//';

Neater (but any safer?)