Adjust width and height of iframe to fit with content in it

html

iframe

responsive-design

jquery

byAlex Kataev·Aug 9, 2024

Ensure a perfectly fitting iframe by using the Window.postMessage() method. Your iframe's content should dispatch its dimensions to the parent document, which subsequently adjusts the iframe styles to accommodate the content appropriately.

Parent Page:

// Listen for any lovely messages from our little iframes
window.addEventListener('message', function(e) {
    var iframe = document.getElementById('myIframe');
    // Time to grow up little iframe
    iframe.style.height = e.data.height + 'px';
    iframe.style.width = e.data.width + 'px';
    // Ah, they grow so fast...
}, false);

Iframe Content:

// Whisper sweet dimensions to the parent window
parent.postMessage({
    height: document.body.scrollHeight,
    width: document.documentElement.scrollWidth
    // It's like sharing your dessert size with your parent
}, '*');

Using the postMessage pattern ensures the parent dynamically adjusts the iframe size based on content changes. Replace '*' with the parent domain for enhanced security.

Step-by-step guide to dynamic sizing

Implementing dynamic iframe sizing can be a tough challenge. Here are some sure-fire steps to ensure success:

Initializing the onload event

An onload event set on the iframe triggers a size-adjusting function, a great starting point for static content.

Monitoring content for changes

Use the MutationObserver to monitor dynamic content. It watches for changes and triggers resizing when needed.

Looping through multiple iframes

Don’t forget to loop through all iframes on your page and adjust their size individually.

Full-proof methods for various circumstances

Overcoming cross-domain constraints

Worried about cross-domain iframes? Resort to postMessage to ensure secure communication for size adjustments. Look into iframe-resizer, an ideal open-source library for cross-domain circumstances.

Adapting styles for responsive design

Prioritize optimizing the initial style settings of iframes to create a genuinely responsive design. Update sizes frequently to ensure responsiveness.