JavaScript window resize event

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How can I hook into a browser window resize event?

There’s a jQuery way of listening for resize events but I would prefer not to bring it into my project for just this one requirement.

First answer

jQuery is just wrapping the standard resize DOM event, eg.

window.onresize = function(event) {
    ...
};

jQuery may do some work to ensure that the resize event gets fired consistently in all browsers, but I’m not sure if any of the browsers differ, but I’d encourage you to test in Firefox, Safari, and IE.

Second answer

First off, I know the addEventListener method has been mentioned in the comments above, but I didn’t see any code. Since it’s the preferred approach, here it is:

window.addEventListener('resize', function(event){
  // do stuff here
});

Here’s a working sample.

Third answer

The resize event should never be used directly as it is fired continuously as we resize.

Use a debounce function to mitigate the excess calls.

window.addEventListener('resize',debounce(handler, delay, immediate),false);

Here’s a common debounce floating around the net, though do look for more advanced ones as featuerd in lodash.

const debounce = (func, wait, immediate) => {
    var timeout;
    return () => {
        const context = this, args = arguments;
        const later = function() {
            timeout = null;
            if (!immediate) func.apply(context, args);
        };
        const callNow = immediate && !timeout;
        clearTimeout(timeout);
        timeout = setTimeout(later, wait);
        if (callNow) func.apply(context, args);
    };
};

This can be used like so…

window.addEventListener('resize', debounce(() => console.log('hello'),
200, false), false);

It will never fire more than once every 200ms.

For mobile orientation changes use:

window.addEventListener('orientationchange', () => console.log('hello'), false);

Here’s a small library I put together to take care of this neatly.

Reprint:https://stackoverflow.com/questions/641857/javascript-window-resize-event
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