IFRAME contentWindow is null
I like clean code so I do what I can to avoid unwanted JavaScript global variables. I initially thought that keys(window) would give me window property leaks but that didn't work because browsers returned different results, so I moved on to using an IFRAME to compare default window property keys.
When I first tried this method, I got a lame error about an IFRAME element's contentWindow property being null. Ugh. It didn't take long to figure out why: you need to wait until the IFRAME has loaded to get the contentWindow:
var iframe = document.createElement('iframe');
iframe.onload = function() {
// contentWindow is set!
};
iframe.src = 'about:blank';
document.body.appendChild(iframe);
Of course you'll want to add the onload event before setting the src. If you use the load event to check for the contentWindow property, you'll be in business!
![Send Text Messages with PHP]()
Kids these days, I tell ya. All they care about is the technology. The video games. The bottled water. Oh, and the texting, always the texting. Back in my day, all we had was...OK, I had all of these things too. But I still don't get...
![Create a CSS Flipping Animation]()
CSS animations are a lot of fun; the beauty of them is that through many simple properties, you can create anything from an elegant fade in to a WTF-Pixar-would-be-proud effect. One CSS effect somewhere in between is the CSS flip effect, whereby there's...
![Google Font API]()
Google recently debuted a new web service called the Font API. Google's Font API provides developers a means by which they may quickly and painlessly add custom fonts to their website. Let's take a quick look at the ways by which the Google Font...
![MooTools Kwicks Plugin]()
I wrote a post titled Get Slick with MooTools Kwicks ages ago. The post was quite popular and the effect has been used often. Looking back now, the original code doesn't look as clean as it could. I've revised the original...
Don’t you need to append your iframe element to a DOM tree so that the browser fetches its target content ? I mean, I know that old IE will load scripts as you parse an “HTML string” but in modern browsers, I thought that the asset does not get loaded until you append the element to a document (and in my opinion this it what makes constructors such as
Image()so useful).Yes, good catch! Updated!
Unfortunately this does not appear to be 100% reliable in chrome (i’m currently using version 62.0.3202.94, but this appears to have been an issue for a while), as sometimes contentWindow can still be null when onload is triggered.
This solution worked for me! Thanks a lot!
Thank you, saved me hours!
Sharry