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paulirish /
Last active Jun 24, 2021
What forces layout/reflow. The comprehensive list.

What forces layout / reflow

All of the below properties or methods, when requested/called in JavaScript, will trigger the browser to synchronously calculate the style and layout*. This is also called reflow or layout thrashing, and is common performance bottleneck.

Generally, all APIs that synchronously provide layout metrics will trigger forced reflow / layout. Read on for additional cases and details.

Element APIs

Getting box metrics
  • elem.offsetLeft, elem.offsetTop, elem.offsetWidth, elem.offsetHeight, elem.offsetParent
mgol /
Last active Mar 8, 2021
How to easily not serve JS and/or CSS to IE<11

Here's how to make your site not load CSS and/or JS in IE older than 11:

<!DOCTYPE html>
        <meta charset="utf-8">
        <meta http-equiv="X-UA-Compatible" content="IE=8,9,11">
        <title>Page title</title>
        <!--[if !IE]>-->
        <link rel="stylesheet" href="styles.css">