How do you add CSS rules (eg strong { color: red }
) by use of Javascript?
This question is related to
javascript
css
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.type = "text/css"
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);
}
You can add classes or style attributes on an element by element basis.
For example:
<a name="myelement" onclick="this.style.color='#FF0';">text</a>
Where you could do this.style.background, this.style.font-size, etc. You can also apply a style using this same method ala
this.className='classname';
If you want to do this in a javascript function, you can use getElementByID rather than 'this'.
use .css
in Jquery like $('strong').css('background','red');
$('strong').css('background','red');
_x000D_
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>_x000D_
<strong> Example_x000D_
</strong>
_x000D_
Here's my general-purpose function which parametrizes the CSS selector and rules, and optionally takes in a css filename (case-sensitive) if you wish to add to a particular sheet instead (otherwise, if you don't provide a CSS filename, it will create a new style element and append it to the existing head. It will make at most one new style element and re-use it on future function calls). Works with FF, Chrome, and IE9+ (maybe earlier too, untested).
function addCssRules(selector, rules, /*Optional*/ sheetName) {
// We want the last sheet so that rules are not overridden.
var styleSheet = document.styleSheets[document.styleSheets.length - 1];
if (sheetName) {
for (var i in document.styleSheets) {
if (document.styleSheets[i].href && document.styleSheets[i].href.indexOf(sheetName) > -1) {
styleSheet = document.styleSheets[i];
break;
}
}
}
if (typeof styleSheet === 'undefined' || styleSheet === null) {
var styleElement = document.createElement("style");
styleElement.type = "text/css";
document.head.appendChild(styleElement);
styleSheet = styleElement.sheet;
}
if (styleSheet) {
if (styleSheet.insertRule)
styleSheet.insertRule(selector + ' {' + rules + '}', styleSheet.cssRules.length);
else if (styleSheet.addRule)
styleSheet.addRule(selector, rules);
}
}
Here's a slightly updated version of Chris Herring's solution, taking into account that you can use innerHTML
as well instead of a creating a new text node:
function insertCss( code ) {
var style = document.createElement('style');
style.type = 'text/css';
if (style.styleSheet) {
// IE
style.styleSheet.cssText = code;
} else {
// Other browsers
style.innerHTML = code;
}
document.getElementsByTagName("head")[0].appendChild( style );
}
if you know at least one <style>
tag exist in page , use this function :
CSS=function(i){document.getElementsByTagName('style')[0].innerHTML+=i};
usage :
CSS("div{background:#00F}");
Shortest One Liner
// One liner function:
const addCSS = s => document.head.appendChild(document.createElement("style")).innerHTML=s;
// Usage:
addCSS("body{ background:red; }")
_x000D_
This easy example of add <style>
in head of html
var sheet = document.createElement('style');
sheet.innerHTML = "table th{padding-bottom: 0 !important;padding-top: 0 !important;}\n"
+ "table ul { margin-top: 0 !important; margin-bottom: 0 !important;}\n"
+ "table td{padding-bottom: 0 !important;padding-top: 0 !important;}\n"
+ ".messages.error{display:none !important;}\n"
+ ".messages.status{display:none !important;} ";
document.body.appendChild(sheet); // append in body
document.head.appendChild(sheet); // append in head
This is my solution to add a css rule at the end of the last style sheet list:
var css = new function()
{
function addStyleSheet()
{
let head = document.head;
let style = document.createElement("style");
head.appendChild(style);
}
this.insert = function(rule)
{
if(document.styleSheets.length == 0) { addStyleSheet(); }
let sheet = document.styleSheets[document.styleSheets.length - 1];
let rules = sheet.rules;
sheet.insertRule(rule, rules.length);
}
}
css.insert("body { background-color: red }");
YUI just recently added a utility specifically for this. See stylesheet.js here.
Here's a sample template to help you get started
Requires 0 libraries and uses only javascript to inject both HTML and CSS.
The function was borrowed from the user @Husky above
Useful if you want to run a tampermonkey script and wanted to add a toggle overlay on a website (e.g. a note app for instance)
// INJECTING THE HTML_x000D_
document.querySelector('body').innerHTML += '<div id="injection">Hello World</div>';_x000D_
_x000D_
// CSS INJECTION FUNCTION_x000D_
//https://stackoverflow.com/questions/707565/how-do-you-add-css-with-javascript_x000D_
function insertCss( code ) {_x000D_
var style = document.createElement('style');_x000D_
style.type = 'text/css';_x000D_
if (style.styleSheet) {_x000D_
// IE_x000D_
style.styleSheet.cssText = code;_x000D_
} else {_x000D_
// Other browsers_x000D_
style.innerHTML = code;_x000D_
}_x000D_
document.getElementsByTagName("head")[0].appendChild( style );_x000D_
}_x000D_
_x000D_
// INJECT THE CSS INTO FUNCTION_x000D_
// Write the css as you normally would... but treat it as strings and concatenate for multilines_x000D_
insertCss(_x000D_
"#injection {color :red; font-size: 30px;}" +_x000D_
"body {background-color: lightblue;}"_x000D_
)
_x000D_
Another option is to use JQuery to store the element's in-line style property, append to it, and to then update the element's style property with the new values. As follows:
function appendCSSToElement(element, CssProperties)
{
var existingCSS = $(element).attr("style");
if(existingCSS == undefined) existingCSS = "";
$.each(CssProperties, function(key,value)
{
existingCSS += " " + key + ": " + value + ";";
});
$(element).attr("style", existingCSS);
return $(element);
}
And then execute it with the new CSS attributes as an object.
appendCSSToElement("#ElementID", { "color": "white", "background-color": "green", "font-weight": "bold" });
This may not necessarily be the most efficient method (I'm open to suggestions on how to improve this. :) ), but it definitely works.
Source: Stackoverflow.com