Is there a TamperMonkey equivalent to GreaseMonkey's GM_addStyle
method for adding CSS?
In GreaseMonkey, you can add a bunch of CSS properties to multiple elements like so:
GM_addStyle("body { color: white; background-color: black; } img { border: 0; }");
To do the equivalent in TamperMonkey, I'm currently having to do the following:
function addGlobalStyle(css) {
var head, style;
head = document.getElementsByTagName('head')[0];
if (!head) { return; }
style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = css;
head.appendChild(style);
}
addGlobalStyle('body { color: white; background-color: black; }');
This works, but is there a built-in GM_addStyle
equivalent for TamperMonkey that saves me from having to repeat this on every script?
ReferenceError: GM_addStyle is not defined
You need to create your own GM_addStyle function, like this :
// ==UserScript==
// @name Example
// @description Usercript with GM_addStyle method.
// ==/UserScript==
function GM_addStyle(css) {
const style = document.getElementById("GM_addStyleBy8626") || (function() {
const style = document.createElement('style');
style.type = 'text/css';
style.id = "GM_addStyleBy8626";
document.head.appendChild(style);
return style;
})();
const sheet = style.sheet;
sheet.insertRule(css, (sheet.rules || sheet.cssRules || []).length);
}
//demo :
GM_addStyle("p { color:red; }");
GM_addStyle("p { text-decoration:underline; }");
document.body.innerHTML = "<p>I used GM_addStyle.</p><pre></pre>";
const sheet = document.getElementById("GM_addStyleBy8626").sheet,
rules = (sheet.rules || sheet.cssRules);
for (let i=0; i<rules.length; i++)
document.querySelector("pre").innerHTML += rules[i].cssText + "\n";
If GM_addStyle(...)
doesn't work, check if you have @grant GM_addStyle
header.
Like this :
// ==UserScript==
// @name Example
// @description See usercript with grant header.
// @grant GM_addStyle
// ==/UserScript==
GM_addStyle("body { color: white; background-color: black; } img { border: 0; }");