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paulirish / what-forces-layout.md
Last active Apr 16, 2021
What forces layout/reflow. The comprehensive list.
View what-forces-layout.md

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
@paulirish
paulirish / performance.now()-polyfill.js
Last active Apr 14, 2021
performance.now() polyfill (aka perf.now())
View performance.now()-polyfill.js
// @license http://opensource.org/licenses/MIT
// copyright Paul Irish 2015
// Date.now() is supported everywhere except IE8. For IE8 we use the Date.now polyfill
// github.com/Financial-Times/polyfill-service/blob/master/polyfills/Date.now/polyfill.js
// as Safari 6 doesn't have support for NavigationTiming, we use a Date.now() timestamp for relative values
// if you want values similar to what you'd get with real perf.now, place this towards the head of the page
// but in reality, you're just getting the delta between now() calls, so it's not terribly important where it's placed
View bling.js
/* bling.js */
window.$ = document.querySelectorAll.bind(document);
Node.prototype.on = window.on = function (name, fn) {
this.addEventListener(name, fn);
}
NodeList.prototype.__proto__ = Array.prototype;
@paulirish
paulirish / how-to-view-source-of-chrome-extension.md
Last active Apr 11, 2021
How to view-source of a Chrome extension
View how-to-view-source-of-chrome-extension.md

Option 1: Command-line download extension as zip and extract

extension_id=jifpbeccnghkjeaalbbjmodiffmgedin   # change this ID
curl -L -o "$extension_id.zip" "https://clients2.google.com/service/update2/crx?response=redirect&os=mac&arch=x86-64&nacl_arch=x86-64&prod=chromecrx&prodchannel=stable&prodversion=44.0.2403.130&x=id%3D$extension_id%26uc" 
unzip -d "$extension_id-source" "$extension_id.zip"

Thx to crxviewer for the magic download URL.

View open-chrome-tabs-in-safari.scpt
tell application "Google Chrome"
set tab_list to every tab in the front window
repeat with the_tab in tab_list
set the_url to the URL of the_tab
tell application "Safari" to open location the_url
end repeat
end tell
@paulirish
paulirish / args.gn
Last active Apr 5, 2021
How to build Chromium to hack on DevTools
View args.gn
# Build arguments for the gn build
# You can set these with `gn args out/Default`
# ( and they're stored in src/out/Default/args.gn )
# See "gn args out/Default --list" for available build arguments
# component build, because people love it
is_component_build = true
# release build, because its faster
is_debug = false
@paulirish
paulirish / asciiify-the-canvas.js
Last active Apr 5, 2021
ascii rendering of a canvas
View asciiify-the-canvas.js
// works great on about:dino
// 1. save this file to your snippets.
// 2. load about:dino
// 3. evaluate the snippet
// 4. hit up arrow to trigger the game.
// 5. profit
(function() {
perfnow = performance.now;
@paulirish
paulirish / rAF.js
Last active Apr 1, 2021
requestAnimationFrame polyfill
View rAF.js
// http://paulirish.com/2011/requestanimationframe-for-smart-animating/
// http://my.opera.com/emoller/blog/2011/12/20/requestanimationframe-for-smart-er-animating
// requestAnimationFrame polyfill by Erik Möller. fixes from Paul Irish and Tino Zijdel
// MIT license
(function() {
var lastTime = 0;
var vendors = ['ms', 'moz', 'webkit', 'o'];
@paulirish
paulirish / gist:5558557
Last active Mar 23, 2021
a brief history of detecting local storage
View gist:5558557

A timeline of the last four years of detecting good old window.localStorage.


Jan Lenhart, bless his heart contributed the first patch for support:

October 2009: 5059daa

View how to screencapture and make animated gifs or whathaveyou.md

Screencapture and animated gifs

I say "animated gif" but in reality I think it's irresponsible to be serving "real" GIF files to people now. You should be serving gfy's, gifv's, webm, mp4s, whatever. They're a fraction of the filesize making it easier for you to deliver high fidelity, full color animation very quickly, especially on bad mobile connections. (But I suppose if you're just doing this for small audiences (like bug reporting), then LICEcap is a good solution).

Capturing (Easy)

  1. Launch quicktime player
  2. do Screen recording

screen shot 2014-10-22 at 11 16 23 am