Evgeny Khoroshilov XOP

CSS Layout Debugger

A tweet-sized debugger for visualizing your CSS layouts. Outlines every DOM element on your page a random (valid) CSS hex color.

One-line version to paste in your DevTools

Use $$ if your browser aliases it:

~ 108 byte version

The Ultimate Unit Testing Cheat-sheet

Sinon Chai
Chai
Sinon

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

	// 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'];

	(function() {
	var CSSCriticalPath = function(w, d, opts) {
	var opt = opts \|\| {};
	var css = {};
	var pushCSS = function(r) {
	if(!!css[r.selectorText] === false) css[r.selectorText] = {};
	var styles = r.style.cssText.split(/;(?![A-Za-z0-9])/);
	for(var i = 0; i < styles.length; i++) {
	if(!!styles[i] === false) continue;
	var pair = styles[i].split(": ");

	var gulp = require('gulp');
	var sourcemaps = require('gulp-sourcemaps');
	var source = require('vinyl-source-stream');
	var buffer = require('vinyl-buffer');
	var browserify = require('browserify');
	var watchify = require('watchify');
	var babel = require('babelify');

	function compile(watch) {
	var bundler = watchify(browserify('./src/index.js', { debug: true }).transform(babel));

	<html>
	<!--
	- GIF is too slow
	- flipping colours in JS is easy
	- Using backgroundImage is flickery
	- With preload: fixed!
	-->
	<head>
	<style>
	body {

	license: gpl-3.0
	redirect: https://observablehq.com/@d3/force-directed-tree