Render entire page in grayscale (greyscale). Updated 2017-07-08.
// ==UserScript==
// @name Grayscaler
// @description Render entire page in grayscale (greyscale). Updated 2017-07-08.
// @author Jefferson "jscher2000" Scher
// @namespace JeffersonScher
// @copyright Copyright 2017 Jefferson Scher
// @license MIT
// @include *
// @version 0.5.2
// @grant GM_registerMenuCommand
// @run-at document-start
// ==/UserScript==
function toggleGrayscale(){
var s=document.getElementById('grayscaler_css');
if(s){
if (s.innerHTML.indexOf('(100%)') > -1) {
s.innerHTML='body{transition: filter .2s ease-in-out; filter: grayscale(0%)}';
} else {
s.innerHTML='body{transition: filter .2s ease-in-out; filter: grayscale(100%) !important}';
}
} else {
s=document.createElement('style');
s.id='grayscaler_css';
s.innerHTML='body{filter: grayscale(100%) !important}';
document.getElementsByTagName("head")[0].appendChild(s);
}
}
// Inject style rule when only <html><head>...</head></html> exists
if (document.getElementsByTagName("head").length > 0){
// do not style stand alone image pages
if (document.getElementsByTagName("head")[0].innerHTML.indexOf('TopLevelImageDocument.css') == -1){
toggleGrayscale();
}
}
// Add menu item
GM_registerMenuCommand("Toggle Grayscaler (Alt+g)", toggleGrayscale);
// Add keyboard shortcut: Ctrl+Shift+g
function Gray_hotkey(evt){
if (evt.key == 'g' && evt.altKey) {
toggleGrayscale();
evt.preventDefault();
evt.stopPropagation();
}
}
document.onreadystatechange = function () {
if (document.readyState === "interactive") {
document.body.addEventListener("keypress", Gray_hotkey, true);
}
};