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recursively get CSS from an element and all the childs

So I would like to be able to do something like this:
getRecursiveCSS(document.getElementById('#menubar'))
And I would like it to return a string of CSS, for the main element and all the childs.
This is what I have tried: (does not work)
function fullPath(el){
var names = [];
while (el.parentNode){
if (el.id){
names.unshift('#'+el.id);
break;
}else{
if (el==el.ownerDocument.documentElement) names.unshift(el.tagName);
else{
for (var c=1,e=el;e.previousElementSibling;e=e.previousElementSibling,c++);
names.unshift(el.tagName+":nth-child("+c+")");
}
el=el.parentNode;
}
}
return names.join(" > ");
}
function styleRecursive(elements, css) {
elements = Object.prototype.toString.call(elements) === '[object Array]' ? elements: [elements];
if (elements.length == 0 || typeof elements[0] == 'undefined')
return css;
if (typeof elements[0].querySelector == 'undefined')
return css
if (typeof css == 'undefined')
css = fullPath(elements[0]) + '{' + getComputedStyle(elements[0]).cssText + '}';
else
css += fullPath(elements[0]) + '{' + getComputedStyle(elements[0]).cssText + '}';
_elements = [];
for (var i = 0; i < elements.length; i++) {
for (var ii = 0; ii < elements[i].childNodes.length; ii++)
_elements.push(elements[i].childNodes[ii]);
}
return styleRecursive(_elements, css);
};

i came up with a solution that maybe give you idea about how improve your code. In order to test driving this code I've made an element that have some children in different depths and this code traverse all children by their depth in recursive way to find/get their css. After that, all founded css plus the element name will storage in an object (JSON like) for later use.
Please Note:
1) This code is not bullet proof so you need to add a lot of conditions/checker to make it work for all kind of situations.
2) Tested in chrome.
3) Limited to classes for finding element and its children (easy to upgrade for ids and tags support)
Output:
one : {
display: "block",
position: "relative"
}
two : {
display: "inline-block",
font-family: "Montserrat"
}
three_1 : {
display: "table",
position: "absolute",
left: "0px"
}
four_1 : {
display: "table-cell",
position: "relative"
}
three_2 : {
display: "table",
position: "absolute",
right: "0px"
}
four_2 : {
display: "table-cell",
position: "relative"
}
HTML(Sample):
<div class="one">
<div class="two">
<div class="three_1">
<div class="four_1"></div>
</div>
<div class="three_2">
<div class="four_2"></div>
</div>
</div>
</div>
CSS(Sample):
.one {display:block;position:relative;}
.two {display:inline-block;font-family:'Montserrat';}
.three_1 {display:table;position:absolute;left:0;}
.three_2 {display:table;position:absolute;right:0;}
.four_1 {display:table-cell;position:relative;}
.four_2 {display:table-cell;position:relative;}
JS:
function convertObjlike(css) {
var s = {};
if (!css) return s;
css = css.split("; ");
for (var i in css) {
var l = css[i].split(": ");
s[l[0].toLowerCase()] = (l[1]);
}
return s;
}
function getCss(a) {
var sheets = document.styleSheets, o = {};
for (var i in sheets) {
var rules = sheets[i].rules || sheets[i].cssRules;
for (var r in rules) {
if (a === rules[r].selectorText) {
o = convertObjlike(rules[r].style.cssText);
}
}
}
return o;
}
var anObject = {};
function styleRecursive(element){
anObject[element.className] = (getCss('.'+element.className));
var children = element.children;
for (var i = 0; i < children.length; i++) {
styleRecursive(children[i])
}
}
styleRecursive( document.querySelector('.one') );
console.log(anObject);
Jsfiddle

EDIT: note that this solution returns the HTML copy, and not the CSS 'file'.
Here is my attempt. It gets every computed style of the element and stores it in the style attribute. It also removes the class attribute since in most cases it is used only for setting those styles (you can remove the removeAttribute call if you want). And it iterate over its children to compute recursively the resulting HTML.
The resulting HTML is huge, as a lot of styles are just the default value, and it isn't optimized for inherit styles, so every child gets all its styles again. Font faces must be imported/registred separately.
Hover effects and media queries does not get copied, since the getComputedStyle captures only the current state of the node. Relative units like vw, vh, %, etc, also gets fixed to the current absolute value. For the same reason, variables are lost and its values are used instead.
function getElemHtml(elem) {
let style = [], computed = window.getComputedStyle(elem)
for (const attr of computed) style.push(`${attr}:${computed[attr]}`)
let clone = elem.cloneNode()
clone.setAttribute('style', style.join(";"))
clone.removeAttribute('class')
let childrenHTML = ''
for (const child of elem.childNodes) childrenHTML += child.nodeType === Element.ELEMENT_NODE ? getElemHtml(child) : child.nodeType === Element.TEXT_NODE ? child.nodeValue : ''
clone.innerHTML = childrenHTML
return clone.outerHTML
}
const elem = document.querySelector("p")
const elemHtml = getElemHtml(elem)
document.querySelector("code").innerText = elemHtml
p {
width: 400px;
margin: 0 auto;
padding: 20px;
font: 2rem/2 sans-serif;
text-align: center;
background: purple;
color: white;
}
pre, code {
width: 90vw;
white-space: pre-wrap;
}
<p>Hello</p>
<pre><code></code></pre>

javascript appending span to text [duplicate]

This question already has answers here:
How to append text to a div element?
(12 answers)
Closed 5 years ago.
I'm currently trying to build my javascript function that gives css styles to every character in an element. Specifically, this function takes in an element, takes the text content in it, stores the text into an array and then create a bunch of spans to append to the text. Right now it seems like my code runs and when I check the variables in chrome dev tools, they return the correct values. However, when I actually implement this code, nothing changes visually but in the dev tools, I get my correct value of <span style="style i chose" > text </span>. Not sure what I did wrong here
var array = [];
var spanarray = [];
var words = document.getElementsByClassName("example")[0];
function fadeInByLetter () {
for(var i = 0; i < words.innerHTML.length;i++){
array.push(words.innerHTML[i]);
var span = document.createElement("span");
var textNode = document.createTextNode(array[i]);
span.appendChild(textNode);
var spancomplete = span;
spanarray.push(spancomplete);
}
for(var i = 0; i < array.length;i++){
spanarray[i].style.color = "red";
spanarray[i].style.background = "pink";
}
}
fadeInByLetter();

var array = [];
var spanarray = [];
var words = document.getElementsByClassName("example")[0];
function fadeInByLetter () {
for(var i = 0; i < words.innerHTML.length;i++){
array.push(words.innerHTML[i]);
var span = document.createElement("span");
var textNode = document.createTextNode(array[i]);
span.appendChild(textNode);
var spancomplete = span;
spanarray.push(spancomplete);
}
words.innerHTML="";
for(var i = 0; i < array.length;i++){
spanarray[i].style.color = "red";
spanarray[i].style.background = "pink";
words.appendChild(spanarray[i]);
}
}
fadeInByLetter();
The solution above should fix the problem. However you have some performance issues. You should save words.innerHTML in a string first. Then use the string instead of words.innerHTML.

That should do the trick:
function fadeInByLetter (wordsContainer) {
// extract text from the container and transform into array
var chars = wordsContainer.innerHTML.split('')
//clear the container
while (wordsContainer.firstChild) {
wordsContainer.removeChild(wordsContainer.firstChild);
}
for(var i = 0; i < chars.length;i++){
var span = document.createElement("span");
var textNode = document.createTextNode(chars[i]);
span.appendChild(textNode);
span.style.color = "red";
span.style.background = "pink";
// append new element
wordsContainer.appendChild(span)
}
}
fadeInByLetter(document.getElementsByClassName("example")[0]);

FYI: There is a library that does this same type of thing.
It's called lettering https://github.com/davatron5000/Lettering.js
Here is a demo using this library.
The library depends upon jQuery but there is also a version of this lib that uses plain javascript. See https://github.com/davatron5000/Lettering.js/wiki/More-Lettering.js
$(document).ready(function() {
$(".example").lettering();
});
//////////////// LETTERING SOURCE BELOW /////////////////////////////
//fadeInByLetter();
/*global jQuery */
/*!
* Lettering.JS 0.7.0
*
* Copyright 2010, Dave Rupert http://daverupert.com
* Released under the WTFPL license
* http://sam.zoy.org/wtfpl/
*
* Thanks to Paul Irish - http://paulirish.com - for the feedback.
*
* Date: Mon Sep 20 17:14:00 2010 -0600
*/
(function($) {
function injector(t, splitter, klass, after) {
var text = t.text(),
a = text.split(splitter),
inject = '';
if (a.length) {
$(a).each(function(i, item) {
inject += '<span class="' + klass + (i + 1) + '" aria-hidden="true">' + item + '</span>' + after;
});
t.attr('aria-label', text)
.empty()
.append(inject)
}
}
var methods = {
init: function() {
return this.each(function() {
injector($(this), '', 'char', '');
});
},
words: function() {
return this.each(function() {
injector($(this), ' ', 'word', ' ');
});
},
lines: function() {
return this.each(function() {
var r = "eefec303079ad17405c889e092e105b0";
// Because it's hard to split a <br/> tag consistently across browsers,
// (*ahem* IE *ahem*), we replace all <br/> instances with an md5 hash
// (of the word "split"). If you're trying to use this plugin on that
// md5 hash string, it will fail because you're being ridiculous.
injector($(this).children("br").replaceWith(r).end(), r, 'line', '');
});
}
};
$.fn.lettering = function(method) {
// Method calling logic
if (method && methods[method]) {
return methods[method].apply(this, [].slice.call(arguments, 1));
} else if (method === 'letters' || !method) {
return methods.init.apply(this, [].slice.call(arguments, 0)); // always pass an array
}
$.error('Method ' + method + ' does not exist on jQuery.lettering');
return this;
};
})(jQuery);
span {
font-size: 74px;
font-family: Arial;
font-weight: 600;
text-transform: uppercase;
letter-spacing: 11px;
display: inline-block;
}
.char1 {
color: red;
transform: rotateZ(-10deg);
}
.char2 {
color: blue;
transform: rotateZ(-12deg);
}
.char3 {
color: purple;
transform: rotateZ(12deg);
}
.char4 {
color: pink;
transform: rotateZ(-22deg);
}
.char5 {
color: yellow;
transform: rotateZ(-12deg);
}
.char6 {
color: gray;
transform: rotateZ(22deg);
}
.char7 {
color: orange;
transform: rotateZ(10deg);
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<span class="example">Example</span>

How to add CSS styles via JavaScript at runtime? [duplicate]

I need to create a CSS stylesheet class dynamically in JavaScript and assign it to some HTML elements like - div, table, span, tr, etc and to some controls like asp:Textbox, Dropdownlist and datalist.
Is it possible?
It would be nice with a sample.

Here is an option:
var style = document.createElement('style');
style.type = 'text/css';
style.innerHTML = '.cssClass { color: #f00; }';
document.getElementsByTagName('head')[0].appendChild(style);
document.getElementById('someElementId').className = 'cssClass';
<div id="someElementId">test text</div>

Found a better solution, which works across all browsers.
Uses document.styleSheet to add or replace rules. Accepted answer is short and handy but this works across IE8 and less too.
function createCSSSelector (selector, style) {
if (!document.styleSheets) return;
if (document.getElementsByTagName('head').length == 0) return;
var styleSheet,mediaType;
if (document.styleSheets.length > 0) {
for (var i = 0, l = document.styleSheets.length; i < l; i++) {
if (document.styleSheets[i].disabled)
continue;
var media = document.styleSheets[i].media;
mediaType = typeof media;
if (mediaType === 'string') {
if (media === '' || (media.indexOf('screen') !== -1)) {
styleSheet = document.styleSheets[i];
}
}
else if (mediaType=='object') {
if (media.mediaText === '' || (media.mediaText.indexOf('screen') !== -1)) {
styleSheet = document.styleSheets[i];
}
}
if (typeof styleSheet !== 'undefined')
break;
}
}
if (typeof styleSheet === 'undefined') {
var styleSheetElement = document.createElement('style');
styleSheetElement.type = 'text/css';
document.getElementsByTagName('head')[0].appendChild(styleSheetElement);
for (i = 0; i < document.styleSheets.length; i++) {
if (document.styleSheets[i].disabled) {
continue;
}
styleSheet = document.styleSheets[i];
}
mediaType = typeof styleSheet.media;
}
if (mediaType === 'string') {
for (var i = 0, l = styleSheet.rules.length; i < l; i++) {
if(styleSheet.rules[i].selectorText && styleSheet.rules[i].selectorText.toLowerCase()==selector.toLowerCase()) {
styleSheet.rules[i].style.cssText = style;
return;
}
}
styleSheet.addRule(selector,style);
}
else if (mediaType === 'object') {
var styleSheetLength = (styleSheet.cssRules) ? styleSheet.cssRules.length : 0;
for (var i = 0; i < styleSheetLength; i++) {
if (styleSheet.cssRules[i].selectorText && styleSheet.cssRules[i].selectorText.toLowerCase() == selector.toLowerCase()) {
styleSheet.cssRules[i].style.cssText = style;
return;
}
}
styleSheet.insertRule(selector + '{' + style + '}', styleSheetLength);
}
}
Function is used as follows.
createCSSSelector('.mycssclass', 'display:none');

Short answer, this is compatible "on all browsers" (specifically, IE8/7):
function createClass(name,rules){
var style = document.createElement('style');
style.type = 'text/css';
document.getElementsByTagName('head')[0].appendChild(style);
if(!(style.sheet||{}).insertRule)
(style.styleSheet || style.sheet).addRule(name, rules);
else
style.sheet.insertRule(name+"{"+rules+"}",0);
}
createClass('.whatever',"background-color: green;");
And this final bit applies the class to an element:
function applyClass(name,element,doRemove){
if(typeof element.valueOf() == "string"){
element = document.getElementById(element);
}
if(!element) return;
if(doRemove){
element.className = element.className.replace(new RegExp("\\b" + name + "\\b","g"));
}else{
element.className = element.className + " " + name;
}
}
Here's a little test page as well: https://gist.github.com/shadybones/9816763
The key little bit is the fact that style elements have a "styleSheet"/"sheet" property which you can use to to add/remove rules on.

There is a light jQuery plugin which allows to generate CSS declarations: jQuery-injectCSS
In fact, it uses JSS (CSS described by JSON), but it's quite easy to handle in order to generate dynamic css stylesheets.
$.injectCSS({
"#test": {
height: 123
}
});

YUI has by far the best stylesheet utility I have seen out there. I encourage you to check it out, but here's a taste:
// style element or locally sourced link element
var sheet = YAHOO.util.StyleSheet(YAHOO.util.Selector.query('style',null,true));
sheet = YAHOO.util.StyleSheet(YAHOO.util.Dom.get('local'));
// OR the id of a style element or locally sourced link element
sheet = YAHOO.util.StyleSheet('local');
// OR string of css text
var css = ".moduleX .alert { background: #fcc; font-weight: bold; } " +
".moduleX .warn { background: #eec; } " +
".hide_messages .moduleX .alert, " +
".hide_messages .moduleX .warn { display: none; }";
sheet = new YAHOO.util.StyleSheet(css);
There are obviously other much simpler ways of changing styles on the fly such as those suggested here. If they make sense for your problem, they might be best, but there are definitely reasons why modifying CSS is a better solution. The most obvious case is when you need to modify a large number of elements. The other major case is if you need your style changes to involve the cascade. Using the DOM to modify an element will always have a higher priority. It's the sledgehammer approach and is equivalent to using the style attribute directly on the HTML element. That is not always the desired effect.

As of IE 9. You can now load a text file and set a style.innerHTML property. So essentially you can now load a css file through ajax (and get the callback) and then just set the text inside of a style tag like this.
This works in other browsers, not sure how far back. But as long as you don't need to support IE8 then it would work.
// RESULT: doesn't work in IE8 and below. Works in IE9 and other browsers.
$(document).ready(function() {
// we want to load the css as a text file and append it with a style.
$.ajax({
url:'myCss.css',
success: function(result) {
var s = document.createElement('style');
s.setAttribute('type', 'text/css');
s.innerHTML = result;
document.getElementsByTagName("head")[0].appendChild(s);
},
fail: function() {
alert('fail');
}
})
});
and then you can have it pull an external file like the myCss.css
.myClass { background:#F00; }

Using google closure:
you can just use the ccsom module:
goog.require('goog.cssom');
var css_node = goog.cssom.addCssText('.cssClass { color: #F00; }');
The javascript code attempts to be cross browser when putting the css node into the document head.

Here is Vishwanath's solution slightly rewritten with comments :
function setStyle(cssRules, aSelector, aStyle){
for(var i = 0; i < cssRules.length; i++) {
if(cssRules[i].selectorText && cssRules[i].selectorText.toLowerCase() == aSelector.toLowerCase()) {
cssRules[i].style.cssText = aStyle;
return true;
}
}
return false;
}
function createCSSSelector(selector, style) {
var doc = document;
var allSS = doc.styleSheets;
if(!allSS) return;
var headElts = doc.getElementsByTagName("head");
if(!headElts.length) return;
var styleSheet, media, iSS = allSS.length; // scope is global in a function
/* 1. search for media == "screen" */
while(iSS){ --iSS;
if(allSS[iSS].disabled) continue; /* dont take into account the disabled stylesheets */
media = allSS[iSS].media;
if(typeof media == "object")
media = media.mediaText;
if(media == "" || media=='all' || media.indexOf("screen") != -1){
styleSheet = allSS[iSS];
iSS = -1; // indication that media=="screen" was found (if not, then iSS==0)
break;
}
}
/* 2. if not found, create one */
if(iSS != -1) {
var styleSheetElement = doc.createElement("style");
styleSheetElement.type = "text/css";
headElts[0].appendChild(styleSheetElement);
styleSheet = doc.styleSheets[allSS.length]; /* take the new stylesheet to add the selector and the style */
}
/* 3. add the selector and style */
switch (typeof styleSheet.media) {
case "string":
if(!setStyle(styleSheet.rules, selector, style));
styleSheet.addRule(selector, style);
break;
case "object":
if(!setStyle(styleSheet.cssRules, selector, style));
styleSheet.insertRule(selector + "{" + style + "}", styleSheet.cssRules.length);
break;
}

One liner, attach one or many new cascading rule(s) to the document.
This example attach a cursor:pointer to every button, input, select.
document.body.appendChild(Object.assign(document.createElement("style"), {textContent: "select, button, input {cursor:pointer}"}))

https://jsfiddle.net/xk6Ut/256/
One option to dynamically create and update CSS class in JavaScript:
Using Style Element to create a CSS section
Using an ID for the style element so that we can update the CSS
class
.....
function writeStyles(styleName, cssText) {
var styleElement = document.getElementById(styleName);
if (styleElement)
document.getElementsByTagName('head')[0].removeChild(
styleElement);
styleElement = document.createElement('style');
styleElement.type = 'text/css';
styleElement.id = styleName;
styleElement.innerHTML = cssText;
document.getElementsByTagName('head')[0].appendChild(styleElement);
}
...
var cssText = '.testDIV{ height:' + height + 'px !important; }';
writeStyles('styles_js', cssText)

An interesting project which could help you out in your task is JSS.
JSS is an authoring tool for CSS which allows you to use JavaScript to describe styles in a declarative, conflict-free and reusable way. It can compile in the browser, server-side or at build time in Node.
JSS library allows you to inject in the DOM/head section using the .attach() function.
Repl online version for evaluation.
Further information on JSS.
An example:
// Use plugins.
jss.use(camelCase())
// Create your style.
const style = {
myButton: {
color: 'green'
}
}
// Compile styles, apply plugins.
const sheet = jss.createStyleSheet(style)
// If you want to render on the client, insert it into DOM.
sheet.attach()

I was looking through some of the answers here, and I couldn't find anything that automatically adds a new stylesheet if there are none, and if not simply modifies an existing one that already contains the style needed, so I made a new function (should work accross all browsers, though not tested, uses addRule and besides that only basic native JavaScript, let me know if it works):
function myCSS(data) {
var head = document.head || document.getElementsByTagName("head")[0];
if(head) {
if(data && data.constructor == Object) {
for(var k in data) {
var selector = k;
var rules = data[k];
var allSheets = document.styleSheets;
var cur = null;
var indexOfPossibleRule = null,
indexOfSheet = null;
for(var i = 0; i < allSheets.length; i++) {
indexOfPossibleRule = findIndexOfObjPropInArray("selectorText",selector,allSheets[i].cssRules);
if(indexOfPossibleRule != null) {
indexOfSheet = i;
break;
}
}
var ruleToEdit = null;
if(indexOfSheet != null) {
ruleToEdit = allSheets[indexOfSheet].cssRules[indexOfPossibleRule];
} else {
cur = document.createElement("style");
cur.type = "text/css";
head.appendChild(cur);
cur.sheet.addRule(selector,"");
ruleToEdit = cur.sheet.cssRules[0];
console.log("NOPE, but here's a new one:", cur);
}
applyCustomCSSruleListToExistingCSSruleList(rules, ruleToEdit, (err) => {
if(err) {
console.log(err);
} else {
console.log("successfully added ", rules, " to ", ruleToEdit);
}
});
}
} else {
console.log("provide one paramter as an object containing the cssStyles, like: {\"#myID\":{position:\"absolute\"}, \".myClass\":{background:\"red\"}}, etc...");
}
} else {
console.log("run this after the page loads");
}
};
then just add these 2 helper functions either inside the above function, or anywhere else:
function applyCustomCSSruleListToExistingCSSruleList(customRuleList, existingRuleList, cb) {
var err = null;
console.log("trying to apply ", customRuleList, " to ", existingRuleList);
if(customRuleList && customRuleList.constructor == Object && existingRuleList && existingRuleList.constructor == CSSStyleRule) {
for(var k in customRuleList) {
existingRuleList["style"][k] = customRuleList[k];
}
} else {
err = ("provide first argument as an object containing the selectors for the keys, and the second argument is the CSSRuleList to modify");
}
if(cb) {
cb(err);
}
}
function findIndexOfObjPropInArray(objPropKey, objPropValue, arr) {
var index = null;
for(var i = 0; i < arr.length; i++) {
if(arr[i][objPropKey] == objPropValue) {
index = i;
break;
}
}
return index;
}
(notice that in both of them I use a for loop instead of .filter, since the CSS style / rule list classes only have a length property, and no .filter method.)
Then to call it:
myCSS({
"#coby": {
position:"absolute",
color:"blue"
},
".myError": {
padding:"4px",
background:"salmon"
}
})
Let me know if it works for your browser or gives an error.

Looked through the answers and the most obvious and straight forward is missing: use document.write() to write out a chunk of CSS you need.
Here is an example (view it on codepen: http://codepen.io/ssh33/pen/zGjWga):
<style>
#import url(http://fonts.googleapis.com/css?family=Open+Sans:800);
.d, body{ font: 3vw 'Open Sans'; padding-top: 1em; }
.d {
text-align: center; background: #aaf;
margin: auto; color: #fff; overflow: hidden;
width: 12em; height: 5em;
}
</style>
<script>
function w(s){document.write(s)}
w("<style>.long-shadow { text-shadow: ");
for(var i=0; i<449; i++) {
if(i!= 0) w(","); w(i+"px "+i+"px #444");
}
w(";}</style>");
</script>
<div class="d">
<div class="long-shadow">Long Shadow<br> Short Code</div>
</div>

For the benefit of searchers; if you are using jQuery, you can do the following:
var currentOverride = $('#customoverridestyles');
if (currentOverride) {
currentOverride.remove();
}
$('body').append("<style id=\"customoverridestyles\">body{background-color:pink;}</style>");
Obviously you can change the inner css to whatever you want.
Appreciate some people prefer pure JavaScript, but it works and has been pretty robust for writing/overwriting styles dynamically.

function createCSSClass(selector, style, hoverstyle)
{
if (!document.styleSheets)
{
return;
}
if (document.getElementsByTagName("head").length == 0)
{
return;
}
var stylesheet;
var mediaType;
if (document.styleSheets.length > 0)
{
for (i = 0; i < document.styleSheets.length; i++)
{
if (document.styleSheets[i].disabled)
{
continue;
}
var media = document.styleSheets[i].media;
mediaType = typeof media;
if (mediaType == "string")
{
if (media == "" || (media.indexOf("screen") != -1))
{
styleSheet = document.styleSheets[i];
}
}
else if (mediaType == "object")
{
if (media.mediaText == "" || (media.mediaText.indexOf("screen") != -1))
{
styleSheet = document.styleSheets[i];
}
}
if (typeof styleSheet != "undefined")
{
break;
}
}
}
if (typeof styleSheet == "undefined") {
var styleSheetElement = document.createElement("style");
styleSheetElement.type = "text/css";
document.getElementsByTagName("head")[0].appendChild(styleSheetElement);
for (i = 0; i < document.styleSheets.length; i++) {
if (document.styleSheets[i].disabled) {
continue;
}
styleSheet = document.styleSheets[i];
}
var media = styleSheet.media;
mediaType = typeof media;
}
if (mediaType == "string") {
for (i = 0; i < styleSheet.rules.length; i++)
{
if (styleSheet.rules[i].selectorText.toLowerCase() == selector.toLowerCase())
{
styleSheet.rules[i].style.cssText = style;
return;
}
}
styleSheet.addRule(selector, style);
}
else if (mediaType == "object")
{
for (i = 0; i < styleSheet.cssRules.length; i++)
{
if (styleSheet.cssRules[i].selectorText.toLowerCase() == selector.toLowerCase())
{
styleSheet.cssRules[i].style.cssText = style;
return;
}
}
if (hoverstyle != null)
{
styleSheet.insertRule(selector + "{" + style + "}", 0);
styleSheet.insertRule(selector + ":hover{" + hoverstyle + "}", 1);
}
else
{
styleSheet.insertRule(selector + "{" + style + "}", 0);
}
}
}
createCSSClass(".modalPopup .header",
" background-color: " + lightest + ";" +
"height: 10%;" +
"color: White;" +
"line-height: 30px;" +
"text-align: center;" +
" width: 100%;" +
"font-weight: bold; ", null);

Here is my modular solution:
var final_style = document.createElement('style');
final_style.type = 'text/css';
function addNewStyle(selector, style){
final_style.innerHTML += selector + '{ ' + style + ' } \n';
};
function submitNewStyle(){
document.getElementsByTagName('head')[0].appendChild(final_style);
final_style = document.createElement('style');
final_style.type = 'text/css';
};
function submitNewStyleWithMedia(mediaSelector){
final_style.innerHTML = '#media(' + mediaSelector + '){\n' + final_style.innerHTML + '\n};';
submitNewStyle();
};
You basically anywhere in your code do:
addNewStyle('body', 'color: ' + color1); , where color1 is defined variable.
When you want to "post" the current CSS file you simply do submitNewStyle(),
and then you can still add more CSS later.
If you want to add it with "media queries", you have the option.
After "addingNewStyles" you simply use submitNewStyleWithMedia('min-width: 1280px');.
It was pretty useful for my use-case, as I was changing CSS of public (not mine) website according to current time. I submit one CSS file before using "active" scripts, and the rest afterwards (makes the site look kinda-like it should before accessing elements through querySelector).

This is what worked for me in Angular:
In HTML I have button with programmatically created CSS with specific ID:
<button [id]="'hoverbutton1'+item.key" [ngClass]="getHoverButtonClass()">
<mat-icon class="icon">open_in_new</mat-icon>
</button>
In typescript I created CSS and assign it to specific element with given ID:
addClasses(){
var style1 = document.createElement('style');
style1.innerHTML = '.hoverbutton'+this.item.key+' { display: none; }';
document.getElementsByTagName('head')[0].appendChild(style1);
}
getHoverButtonClass() {
return "hoverbutton"+this.item.key
}
This way I can create as many CSS classes as I want and assign them to elements individually. :)

How do I supplant jQuery's toggleClass method with pure JavaScript?

How can I turn this piece of jQuery code into JavaScript?
$('#element').click(function(){
$(this).toggleClass('class1 class2')
});
I have already tried the following pieces of code, but to no avail.
First one is:
var element = document.getElementById('element'),
classNum = 0; // Supposing I know that the first time there will be that class
element.onmousedown = function() {
if (classNum === 0) {
this.classList.remove("class1");
this.classList.add("class2");
classNum = 1;
}
else if (classNum === 1) {
this.classList.remove("class2");
this.classList.add("class1");
classNum = 0;
}
}
Second one is:
var element = document.getElementById('element'),
classNum = 0; // Supposing I know that the first time there will be that class
element.onmousedown = function() {
if (classNum === 0) {
this.className -= "class1";
this.classList += "class2";
classNum = 1;
}
else if (classNum === 1) {
this.classList -= "class2";
this.classList += "class1";
classNum = 0;
}
}
Any answer that doesn't suggest that I stick with jQuery will be greatly appreciated.
[EDIT]
I've tried all of your solutions, but haven't been able to get it right. I believe it's because I didn't state clearly that the element has multiple classes like so:
class="class1 class3 class4"
And what I want is basically to replace class1 with class2 and toggle between them.

Update:
In response to comments, classList.toggle is a pure javascript solution. It has nothing to do with jQuery as one comment implies. If there is a requirement to support old versions of IE then there is a shim (pollyfill) at the MDN link below. And this shim, if needed, is far superior to the accepted answer.
Using classList.toggle certainly seems like the simplest solution. Also see Can I Use classList for browser support.
element.onclick = function() {
'class1 class2'.split(' ').forEach(function(s) {
element.classList.toggle(s);
});
}
Run the snippet to try
box.onclick = function() {
'class1 class2'.split(' ').forEach(function(s) {
box.classList.toggle(s);
stdout.innerHTML = box.className;
});
}
/* alternative
box.onclick = function() {
['class1', 'class2'].forEach(function(s) {
box.classList.toggle(s);
stdout.innerHTML = box.className;
});
}
*/
.class1 { background-color: red;}
.class2 { background-color: blue;}
.class3 { width: 100px; height: 100px; border: 1px black solid;}
click me:
<div id="box" class="class1 class3"></div>
<div id="stdout"></div>

classNum is a local variable.
Every time the event handler is called, you get a new variable, which has nothing to do with the value from the last call.
You want that to be a global variable.
Or, better yet, check classList.contains instead.

From: You might not need jQuery
$(el).toggleClass(className);
Is replaced by:
if (el.classList) {
el.classList.toggle(className);
} else {
var classes = el.className.split(' ');
var existingIndex = classes.indexOf(className);
if (existingIndex >= 0)
classes.splice(existingIndex, 1);
else
classes.push(className);
el.className = classes.join(' ');
}
Then simply wrap that function call within a document.getElementById('elementId').click

See fiddle: https://jsfiddle.net/2ch8ztdk/
var s = document.getElementById('element');
s.onclick=function(){
if(s.className == "class1"){
s.className = "class2"
} else {
s.className = "class1"
}
}

Your code is close, but your classNum variable isn't iterative. Try this:
var element = document.getElementById("element");
var numCount = 0;
element.addEventListener('click', function() {
if (numCount === 0) {
this.className = "";
this.className += " class1";
numCount++;
} else {
this.className = "";
this.className += " class2";
numCount = 0;
}
});
.class1 {
color: red;
}
.class2 {
color: blue;
}
<div id="element">click me</div>

you can use classList, but it only support IE 10+
Demo
var eles = document.querySelectorAll('#element');
var classNames = 'one two';
for(var i = 0; i < eles.length; i ++){
eles[i].onclick = function(e){
toggleClass.call(this, classNames);
}
}
function toggleClass(names){
var sp = names.split(' ');
for(var i = 0; i < sp.length; i++){
this.classList.toggle(sp[i]);
}
}

UPDATED MY ANSWER TO SUPPORT MULTIPLE CLASSES PER ELEMENT
https://jsfiddle.net/pwyncL8r/2/ This will now allow the element to already have n classes and still swap only one, retaining the other classes.
HTML
<div id="div1" style="width: 100px; height: 100px;" class="backBlack left100"</div>
<input type="button" id="swapButton" value="Css Swap" />
CSS
.backBlack {
background-color: black;
}
.backRed {
background-color: red;
}
.left100 {
margin-left: 100px;
}
JS
swapButton.onclick = function() {
var curClassIsBlack = (' ' + document.getElementById("div1").className + ' ').indexOf(' backBlack ') > -1
if (curClassIsBlack) {
document.getElementById("div1").className =
document.getElementById("div1").className.replace(/(?:^|\s)backBlack(?!\S)/g, '')
document.getElementById("div1").className += " backRed";
} else {
document.getElementById("div1").className =
document.getElementById("div1").className.replace(/(?:^|\s)backRed(?!\S)/g,'')
document.getElementById("div1").className += " backBlack";
}
}

pure javascript to check if something has hover (without setting on mouseover/out)

I have seen this jQuery syntax:
if($(element).is(':hover')) { do something}
Since I am not using jQuery, I am looking for the best way to do this in pure javascript.
I know I could keep a global variable and set/unset it using mouseover and mouseout, but I'm wondering if there is some way to inspect the element's native properties via the DOM instead? Maybe something like this:
if(element.style.className.hovered === true) {do something}
Also, it must be cross browser compatible.

Simply using element.matches(':hover') seems to work well for me, you can use a comprehensive polyfill for older browsers too: https://developer.mozilla.org/en-US/docs/Web/API/Element/matches

You can use querySelector for IE>=8:
const isHover = e => e.parentElement.querySelector(':hover') === e;
const myDiv = document.getElementById('mydiv');
document.addEventListener('mousemove', function checkHover() {
const hovered = isHover(myDiv);
if (hovered !== checkHover.hovered) {
console.log(hovered ? 'hovered' : 'not hovered');
checkHover.hovered = hovered;
}
});
.whyToCheckMe {position: absolute;left: 100px;top: 50px;}
<div id="mydiv">HoverMe
<div class="whyToCheckMe">Do I need to be checked too?</div>
</div>
to fallback I think it is ok #Kolink answer.

First you need to keep track of which elements are being hovered on. Here's one way of doing it:
(function() {
var matchfunc = null, prefixes = ["","ms","moz","webkit","o"], i, m;
for(i=0; i<prefixes.length; i++) {
m = prefixes[i]+(prefixes[i] ? "Matches" : "matches");
if( document.documentElement[m]) {matchfunc = m; break;}
m += "Selector";
if( document.documentElement[m]) {matchfunc = m; break;}
}
if( matchfunc) window.isHover = function(elem) {return elem[matchfunc](":hover");};
else {
window.onmouseover = function(e) {
e = e || window.event;
var t = e.srcElement || e.target;
while(t) {
t.hovering = true;
t = t.parentNode;
}
};
window.onmouseout = function(e) {
e = e || window.event;
var t = e.srcElement || e.target;
while(t) {
t.hovering = false;
t = t.parentNode;
}
};
window.isHover = function(elem) {return elem.hovering;};
}
})();

it occurred to me that one way to check if an element is being hovered over is to set an unused property in css :hover and then check if that property exists in javascript. its not a proper solution to the problem since it is not making use of a dom-native hover property, but it is the closest and most minimal solution i can think of.
<html>
<head>
<style type="text/css">
#hover_el
{
border: 0px solid blue;
height: 100px;
width: 100px;
background-color: blue;
}
#hover_el:hover
{
border: 0px dashed blue;
}
</style>
<script type='text/javascript'>
window.onload = function() {check_for_hover()};
function check_for_hover() {
var hover_element = document.getElementById('hover_el');
var hover_status = (getStyle(hover_element, 'border-style') === 'dashed') ? true : false;
document.getElementById('display').innerHTML = 'you are' + (hover_status ? '' : ' not') + ' hovering';
setTimeout(check_for_hover, 1000);
};
function getStyle(oElm, strCssRule) {
var strValue = "";
if(document.defaultView && document.defaultView.getComputedStyle) {
strValue = document.defaultView.getComputedStyle(oElm, "").getPropertyValue(strCssRule);
}
else if(oElm.currentStyle) {
strCssRule = strCssRule.replace(/\-(\w)/g, function (strMatch, p1) {
return p1.toUpperCase();
});
strValue = oElm.currentStyle[strCssRule];
}
return strValue;
};
</script>
</head>
<body>
<div id='hover_el'>hover here</div>
<div id='display'></div>
</body>
</html>
(function getStyle thanks to JavaScript get Styles)
if anyone can think of a better css property to use as a flag than solid/dashed please let me know. preferably the property would be one which is rarely used and cannot be inherited.
EDIT: CSS variable are probably better to use to check this. E.g.
const fps = 60;
setInterval(function() {
if(getComputedStyle(document.getElementById('my-div')).getPropertyValue('--hovered') == 1) {
document.getElementById('result').innerHTML = 'Yes';
} else {
document.getElementById('result').innerHTML = 'No';
};
}, 1000 / fps);
#my-div {
--hovered:0;
color: black;
}
#my-div:hover {
--hovered:1;
color: red;
}
<!DOCTYPE html>
<html>
<head>
<title>Detect if div is hovered with JS, using CSS variables</title>
</head>
<body>
<div id="my-div">Am I hovered?</div>
<div id="result"></div>
</body>
</html>

You can use an if statement with a querySelector. If you add ":hover" to the end of the selector, it will only return the element if it is being hovered. This means you can test if it returns null. It is like the element.matches(":hover) solution above, but I have had more success with this version.
Here is an example:
if (document.querySelector("body > p:hover") != null) {
console.log("hovered");
}
You can put it in an interval to run the code every time you hover:
setInterval(() => {
if (document.querySelector("body > p:hover") != null) {
console.log("hovered");
}
}, 10);