iframe automatic height adjustment using HTML5 cross domain web messaging

Yesterday I was working on a site that needed an iframe embedded in the page whose content came from a completely different domain. I try to steer clear of iframes at all costs normally so forgive me if what I’m about to say is pretty obvious.

I didn’t want the content in the iframe to appear as though it was in an iframe, so obviously I stripped off all the default browser styles…well, the border. I wanted the iframe to be as high as the content it was containing so that no scroll bars would appear.

So what I did was just give the iframe a height, however when the user navigated to a different page within the iframe, the height I had previously set was too big or too small.

I instantly thought “right, JavaScript will sort this out for me!” and proceeded to quickly code up a function that would inspect the scrollHeight of the content in the iframe and adjust the iframe height accordingly.

No! Said cross domain policy. I had momentarily forgotten all about that. Since the iframe content came from a different domain, I wasn’t allowed to access the document object of the iframe (or vice versa).

Here is how not to do it

Firefox says “Error: Permission denied to access property ‘document’” and other browsers similar.

I started searching for some kind of workaround.  Of course there isn’t really one…except I did find an interesting hack for Firefox. Which is – an iframe document can alter the url fragment of the parent window’s location object! ha madness.

The idea is that the document in the iframe alters the url fragment to read:

http://freestyle-developments.co.uk/blog/?p=150#138

Where 138 is the height of the iframe document (obviously you could be a bit more fancy and send other parameters and name them e.g #height:138 but for simplicity I’ve just set the value). The parent then reads this value and sets the iframe height accordingly:

var iFrameHeight = parseInt(location.hash.replace('#', ''));

So…yeah, that’s pretty interesting, but not really a solution. Check out the example implementation here.

Anyway, what to do? HTML5 web messaging to the rescue! Sweet! HTML5 web messaging is cross domain messaging done right. Not only does the messenger choose who should receive messages, but the recipient also chooses who to receive messages from.

The idea is that after the iframe document has loaded, it sends a message to the parent window telling it what it’s scrollHeight is. The parent listens for messages, and sets the height of the iframe when it receives a message.

A couple of things to note:

  1. There has to be communication between the two documents. i.e. the document on the external domain needs to actively send this message. Which can be a complete show stopper if you have no control over the document on the external domain
  2. This isn’t going to work on IE < 9. I tested the implementation linked below is working on FireFox 4 (Beta 7), Safari 5.0.2, Chrome 8, Opera 10.63 and Internet Explorer 9 Platform Preview 7. Which is a pretty good spread to be honest

Check out the example HTML5 web messaging implementation here.

11,921 thoughts on “iframe automatic height adjustment using HTML5 cross domain web messaging

  1. промокод мелбет на сегодня Введите: RS777 и тогда при депозите вы получите бонус 50 000 рублей автоматически. Букмекерская контора Мелбет в 2026 году создала комфортные условия для заядлых беттеров и новых пользователей. Международная букмекерская платформа Melbet стремительно набирает популярность среди беттеров. Для привлечения новой аудитории и повышения лояльности уже имеющейся администрация сайта создала специальный промокод.

  2. Начинает формироваться мнение. https://freerockme.com САБЖ САМ ПО СЕБЕ НЕ ПРЁТ МУТИТЬ НА НЁМ МИКСЫ СМЫСЛА НЕТ ЭТО АНТИДЕПРЕССАНТ кто зовет мать и отца.

  3. Монобукет — это когда главный акцент сделан на красоте одного вида цветов, а не на сложных сочетаниях. В каталоге интернет-магазина «Флорион» на странице https://www.florion.ru/catalog/mono-bukety представлены элегантные монобукеты из роз, которые подойдут и для признания в любви, и для делового комплимента. Флористы тщательно подбирают оттенки и степень раскрытости бутонов, создавая композиции, которые выглядят современно, стильно и всегда уместно в городском ритме.

  4. 저희 수원출장마사지 서비스는 바쁜 현대인들에게 맞춤 휴식을
    선사하는 최고의 선택입니다. 이제 시간과 장소의 제약 없이 전문
    마사지사의 체계적인 관리를 받아보세요.

  5. I’ve been researching major rated cookware brands not too long ago, and the comparisons are all around the location. For balanced experiences and genuine-consumer insights, I preserve coming lower back to cookware brand reviews for tips earlier than I buy.

  6. бездепозитные бонусы в казино с выводом без пополнения за регистрацию

  7. Адвокат Лаптинский Игорь Геннадьевич — практик с 17 летним опытом, член Адвокатской палаты МО, уверенно ведет гражданские, семейные, жилищные, трудовые, арбитражные и уголовные дела, предлагая несколько сценариев защиты и гибкую ценовую политику. Офис — Москва, Рязанский проспект, д. 30/15, оф. 413, возможна дистанционная работа и оперативная консультация. Клиенты отмечают стратегичность, конфиденциальность и четкие сроки. Скачайте актуальный прайс, задайте вопрос и получите ответ в 5–10 минут: https://advokat-laptinskiy.ru/

  8. Все вопросы к представителю. купить Мефедрон Бошки Марихуану Это точно главное быть в этом уверенным. Да и ровненький магазин однакоЗахожу 24-го фигакс бан.

  9. Free video chat https://emerald-chat.app/ find people from all over the world in seconds. Anonymous no registration or SMS required. A convenient alternative to Omegle: minimal settings maximum live communication right in your browser at home or on the go without unnecessary ads.

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>