Iframe facts
Key takeaways from Chapter 13: Using Iframes Sparingly of "Even Faster Websites", a guide for performance vigilantes -
TODO: Update SearchLite v2, my 2002 script that uses IFrames & give it a makeover
- Relative URLs inside the iframe are resolved relative to the iframe’s base URI, not the parent’s.
- JavaScript included in the iframe has limited access to the parent.
- An iframe from a different domain can’t access the parent’s cookies.
- Iframes are one to two orders of magnitude more expensive to create than other types of DOM elements.
- An alternative way to insert ads with better performance would be for the main page to create a DIV to hold the contents of the ad.
- We want the onload event to fire as quickly as possible. Iframes block Onload.
- A workaround to blocking behavior in Safari and Chrome is to set the iframe’s URL dynamically with JavaScript instead of setting it with the HTML SRC attribute.
- Resources in an iframe are downloaded in parallel with resources in the main page.
- Using an iframe does not increase the number of parallel downloads for a given hostname.
- The connection pool is shared across tabs and windows for all these browsers.
TODO: Update SearchLite v2, my 2002 script that uses IFrames & give it a makeover
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