How do you add CSS with Javascript?
You can also do this using DOM Level 2 CSS interfaces (MDN):
var sheet = window.document.styleSheets[0];
sheet.insertRule('strong { color: red; }', sheet.cssRules.length);
...on all but (naturally) IE8 and prior, which uses its own marginally-different wording:
sheet.addRule('strong', 'color: red;', -1);
There is a theoretical advantage in this compared to the createElement-set-innerHTML method, in that you don't have to worry about putting special HTML characters in the innerHTML, but in practice style elements are CDATA in legacy HTML, and ‘<’ and ‘&’ are rarely used in stylesheets anyway.
You do need a stylesheet in place before you can started appending to it like this. That can be any existing active stylesheet: external, embedded or empty, it doesn't matter. If there isn't one, the only standard way to create it at the moment is with createElement.
The simple-and-direct approach is to create and add a new style
node to the document.
// Your CSS as text
var styles = `
.qwebirc-qui .ircwindow div {
font-family: Georgia,Cambria,"Times New Roman",Times,serif;
margin: 26px auto 0 auto;
max-width: 650px;
}
.qwebirc-qui .lines {
font-size: 18px;
line-height: 1.58;
letter-spacing: -.004em;
}
.qwebirc-qui .nicklist a {
margin: 6px;
}
`
var styleSheet = document.createElement("style")
styleSheet.innerText = styles
document.head.appendChild(styleSheet)
The solution by Ben Blank wouldn't work in IE8 for me.
However this did work in IE8
function addCss(cssCode) {
var styleElement = document.createElement("style");
styleElement.type = "text/css";
if (styleElement.styleSheet) {
styleElement.styleSheet.cssText = cssCode;
} else {
styleElement.appendChild(document.createTextNode(cssCode));
}
document.getElementsByTagName("head")[0].appendChild(styleElement);
}
Shortest One Liner
// One liner function:
const addCSS = css => document.head.appendChild(document.createElement("style")).innerHTML=css;
// Usage:
addCSS("body{ background:red; }")