iframe without an src attribute

Question

I would like to create an <iframe> on the page, but then add the src later. If I make an iframe without an src attribute, then it loads the current page in some browsers. What is the correct value to set for the src so that it just loads a blank iframe?

The answers I've seen are:

• about:blank
• javascript:false
• javascript:void(0)
• javascript:"";
• url to a blank page

Is there a clear winner? If not, what are the tradeoffs?

I'd like to not have mixed content warnings for HTTPS urls, nor any back-button, history, or reload weirdness in all browsers from IE6 onward.

Answer 1

Not sure if all browsers support "about:blank", so I'd just go with your own blank page then.

Another idea: Why not add the whole iframe using javascript instead of just the src?

Answer 2

Standard approach when creating an "empty" iframe (as an iframe shim, for example), is to set the src as javascript:false;. This is the method used by most of the JavaScript libraries that create iframe shims for you (e.g. YUI's Overlay).