I'm trying to make a page that has 3 buttons that make the background change color. I know how to do this, theoretically. I've been trying to build the methods for changing the background color but whenever I change the color, it's because the new style element overlaps the old one(s), so I'm looking for a way to delete the previous one when the new one is created but I've yet to find it.
var backgroundColor = {
red: function backgroundRed() {
var sheet = document.createElement('style');
sheet.setAttribute('id', 'redBG');
sheet.innerHTML = "body {background-color: red;}";
document.body.appendChild(sheet);
},
blue: function backgroundBlue() {
var sheet = document.createElement('style');
sheet.setAttribute('id', 'blueBG');
sheet.innerHTML = "body {background-color: blue;}";
document.body.appendChild(sheet);
},
green: function backgroundGreen() {
var sheet = document.createElement('style');
sheet.setAttribute('id', 'greenBG');
sheet.innerHTML = "body {background-color: limegreen;}";
document.body.appendChild(sheet);
},
deletePrevious: function() {
// ???
},
};
var applyColor = {
applyRed: function() {
//a method that when applying a new background color deletes the previous one
backgroundColor.red();
},
applyBlue: function() {
backgroundColor.blue();
},
applyGreen: function() {
backgroundColor.green();
}
}
This is the code I've written so far. The thing is, when I run it, this is what happens: Overlapping elements
How can I make a method that deletes the previous elements? Should I nest the elements within a div?
Edit: Turns out I'm wildly overthinking this. I'm been learning JS for about 2 months now, still have a long way to go. Andrew Lohr's comment effectively replaces all the backgroundColor functions I created. I'm also new to StackOverflow so I haven't found a way to upvote his comment yet. I need to get more acquainted with the DOM and easier ways to modify it.
Thank you all for your responses and your help.
You look like you're familiar with JS, so tell me if you need a example.
Make a style tag with the 'themeCSS'. Then, every time you want to add/replace the CSS, use:
themeCSS.innerHTML = "so { and: so; }";
That way, it'll always replace the previous CSS :)
Instead of changing the entire CSS <style> tag just set a value in the class` attribute that sets the overall theme and all of your CSS is based on that theme.
body.theme-red {
background-color: red;
}
body.theme-blue {
background-color: blue;
}
body.theme-green {
background-color: green;
}
.theme-red h1 {
color: black
}
.theme-blue h1 {
color: yellow;
}
.theme-green h1 {
color: red;
}
Or, break your CSS into three files and only load the correct one based on the theme.
Or, break you CSS into three files and use Alternate Style Sheets.
Related
I want to change the background color of a row if the value in the table cell goes above a certain value.
I have tried implementing the toggle class as well as adding and removing classes with no luck. When I manually implemented the background color it worked.
I know I am trying to toggle a class vs a style, but is there any way I can toggle a style to change the background color?
var mq2 = 5;
if (mq2 >= 5) {
document.getElementById("row1").classlist.toggle("change2");
} else {
document.getElementById("row1").classlist.toggle("change1");
}
.change1 {
background-color: #FF6347;
}
.change2 {
background-color: #90EE90;
}
<tr id="row1">
Your code should work. You could improve it by creating a variable referencing the element
const row = document.getElementById("row1");
if(someCondition) {
row.classList.toggle("change2");
} else {
row.classList.toggle("change1");
}
The approach you are taking is fine, just make sure you capitalize classList correctly.
document.getElementById('row1').classList.toggle('change1');
Goal
In my program I want to do both things with jquery/javascript:
Change styling of css classes dynamically
Add/remove classes to elements
Problem
To do the first thing I use $(".className").css() method, but it changes style only for those elements that already have className class, i.e. if I later add className to an element its style won't be new. How can I solve this?
Example
See it also at jsfiddle.
$("p").addClass("redclass");
$(".redclass").css("color", "darkRed");
$("span").addClass("redclass");
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>I want to be red! And I am.</p>
<span>I want to be red too but I'm not :'(</span>
Result:
A more shorten format:
$("<style/>", {text: ".redclass {color: darkRed;}"}).appendTo('head');
The snippet:
$("<style/>", {text: ".redclass {color: darkRed;}"}).appendTo('head');
$("p").addClass("redclass");
$("span").addClass("redclass");
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>I want to be red! And I am.</p>
<span>I want to be red too but I'm not :'(</span>
While other (working) answers have been supplied, they don't actually answer your question - namely, they don't change the specified css class, but instead override it by adding another rule later in the document.
They achieve this, basically:
Before
.someClass
{
color: red;
}
After
.someClass
{
color: red;
}
.someClass
{
color: white;
}
When in many cases, a better option would see the color attribute of the existing rule altered.
Well, as it turns out - the browser maintains a collection of style-sheets, style-sheet rules and attributes of said rules. We may prefer instead, to find the existing rule and alter it. (We would certainly prefer a method that performed error checking over the one I present!)
The first console msg comes from the 1 instance of a #coords rule.
The next three come from the 3 instances of the .that rule
function byId(id){return document.getElementById(id)}
window.addEventListener('load', onDocLoaded, false);
function onDocLoaded(evt)
{
byId('goBtn').addEventListener('click', onGoBtnClicked, false);
}
function onGoBtnClicked(evt)
{
alterExistingCSSRuleAttrib('#coords', 'background-color', 'blue');
alterExistingCSSRuleAttrib('.that', 'color', 'red');
}
// useful for HtmlCollection, NodeList, String types (array-like types)
function forEach(array, callback, scope){for (var i=0,n=array.length; i<n; i++)callback.call(scope, array[i], i, array);} // passes back stuff we need
function alterExistingCSSRuleAttrib(selectorText, tgtAttribName, newValue)
{
var styleSheets = document.styleSheets;
forEach(styleSheets, styleSheetFunc);
function styleSheetFunc(CSSStyleSheet)
{
forEach(CSSStyleSheet.cssRules, cssRuleFunc);
}
function cssRuleFunc(rule)
{
if (selectorText.indexOf(rule.selectorText) != -1)
forEach(rule.style, cssRuleAttributeFunc);
function cssRuleAttributeFunc(attribName)
{
if (attribName == tgtAttribName)
{
rule.style[attribName] = newValue;
console.log('attribute replaced');
}
}
}
}
#coords
{
font-size: 0.75em;
width: 10em;
background-color: red;
}
.that
{
color: blue;
}
<style>.that{color: green;font-size: 3em;font-weight: bold;}</style>
<button id='goBtn'>Change css rules</button>
<div id='coords' class='that'>Test div</div>
<style>.that{color: blue;font-size: 2em;font-weight: bold;}</style>
#synthet1c has described the problem. My solution is:
$("head").append('<style></style>');
var element = $("head").children(':last');
element.html('.redclass{color: darkred;}');
What you are having issue with is that when you use the jQuery selector $('.redclass').css('color', 'darkRed') you are getting all the elements that currently have that class and using javascript to loop over the collection and set the style property.
You then set the class on the span after. Which was not included in the collection at the time of setting the color
You should set the class in your css file so it is distributed to all elements that have that class
console.log($('.redclass').length)
$("p").addClass("redclass");
console.log($('.redclass').length)
// $(".redclass").css("color", "darkRed");
$("span").addClass("redclass");
console.log($('.redclass').length)
.redclass {
color: darkRed;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<p>I want to be red! And I am.</p>
<span>I want to be red too but I'm not :'(</span>
According to This page I was able to remove all the CSS preloaded and added on the webpage using that. I wanted to implement a button system where "onclick" = enable/disable webpage CSS even the ones pre-loaded by my web-host. I would like to eliminate the style tags to prevent lags for my website users. I prefer using the script that I have linked above unless there is another alternative that works better. Is it possible to enable CSS onclick the same button to disable? If not is it possible, can it be done with this quick? example with the preferred script below:
if (disable) {
style = "disable";
} else {
location.reload();
}
PREFERRED SCRIPT:
function removeStyles(el) {
el.removeAttribute('style');
if(el.childNodes.length > 0) {
for(var child in el.childNodes) {
/* filter element nodes only */
if(el.childNodes[child].nodeType == 1)
removeStyles(el.childNodes[child]);
}
}
}
removeStyles(document.body);
What about a different aproach?
Add initially a class to a body called 'styled' for example
<body class="styled">
use it as a main selector in your css definitions
<style>
.styled a { ... }
.styled h1 { .... }
</style>
then an example jquery script to toggle the class:
<script>
$(function() {
$('#myswitch').click(function() {
$('body').toggleClass('styled');
});
});
</script>
when class is present, the page will be styled, when absent there will be no styling.
Of coures there could be better aproach, but this is the first thing which pops up in my mind
To remove all style on an element, you could do
function removeStyles(el) {
el.style = {};
}
If you want to enable/disable the CSS on the page, then the goal is not to merely remove all the styles on the page, but you will need to save them somewhere also so they can be recalled when the user re-clicks the button. I would recommend having jQuery to help you with this, and it could be done the following way:
var style_nodes = $('link[rel="stylesheet"], style');
style_nodes.remove();
$('*').each(function(num, obj) {
var style_string = $(obj).attr("style");
if (style_string) {
$(obj).data("style-string", style_string);
$(obj).attr("style", "");
}
});
Now you've saved the stylesheets and style DOM nodes inside of style_nodes, and the actual style attribute inside of a jQuery data attribute for that specific DOM node. When you click to add the CSS back to the page, you can do the following:
$('head').append(style_nodes);
$('*').each(function(num, obj) {
if ($(obj).data("style-string"))
$(obj).attr("style", $(obj).data("style-string"));
});
Check out this JS Fiddle I put together to demonstrate it:
https://jsfiddle.net/5krLn3w1/
Uses JQuery, but I'm sure most frameworks should give you similar functionality.
HTML:
<h1>Hello World</h1>
Turn off CSS
Turn on CSS
JS:
$(document).ready(function() {
$('a#turn_off').click(function(evt) {
evt.preventDefault();
var css = $('head').find('style[type="text/css"]').add('link[rel="stylesheet"]');
$('head').data('css', css);
css.remove();
});
$('a#turn_on').click(function(evt) {
evt.preventDefault();
var css = $('head').data('css');
console.info(css);
if (css) {
$('head').append(css);
}
});
});
CSS:
body {
color: #00F;
}
h1 {
font-size: 50px;
}
I have been using jss in my project to do dynamic styles. This has worked great for the most part, but I want to do something it seems to not help with.
I want to be able to create a set of main style rules first, then create a set of default style rules that can be overridden by the main style rules if they conflict. Example:
<div class="mainClass1 defaultClass1">text</div>
<script>
jss.set('.mainClass1', {
color: 'red'
})
jss.set('.defaultClass1', {
color: 'green'
})
</script>
I want the outcome to be that the text is red, but the way jss operates, the text comes out green. I was hoping I could somehow create two dynamic stylesheets, the "default" sheet being first, and the "main" sheet being second (so that main overrides default). Is this possible?
Update - I confirmed a technique that works with raw javascript:
var styleNode = document.createElement('style');
styleNode.type = 'text/css';
styleNode.rel = 'stylesheet';
document.head.appendChild(styleNode);
//styleNode.sheet.insertRule("#A" + ' { color:green; }', 1);
var styleNode2 = document.createElement('style');
styleNode2.type = 'text/css';
styleNode2.rel = 'stylesheet';
document.head.appendChild(styleNode2);
styleNode2.sheet.insertRule("#A" + ' { color:green; }', 0);
styleNode.sheet.insertRule("#A" + ' { color:red; }', 0);
The element with id 'A' remains green even after the red style is added on the earlier stylesheet. Now I'm just wondering if I can do this with jss or if I need to roll something of my own.
Why does this not work?
var jss1 = jss.forDocument(document)
var jss2 = jss.forDocument(document)
jss2.set('#A', {
color: 'green'
})
jss1.set('#A', {
color: 'red'
})
A brief inspection of the jss source leads me to believe that your answer lies in creating different stylesheets. From my brief perusal it seems that CSS in stylesheets created later override CSS in previously created stylesheets.
"Read the source"
Using CSS selectors
You can do this very simply, just use the multiple classes selector:
jss.set('.defaultClass1.mainClass1', {...});
This has a higher class specificity than the .defaultClass selector.
Using the JSS-extend plugin
This JSS plugin simplifies extending styles. For example you can do this (copied from an example in the repository.
var button0 = {
padding: '20px',
background: 'blue'
}
var redButton = {
background: 'red'
}
window.styles = {
button0: button0,
button1: {
extend: [button0, redButton],
'font-size': '20px'
}
}
This registers the button0and button1 styles to the current window (just like linking a CSS file).
Allllright, I figured out how to do it with jss:
<div id="a">A div</div>
<script>
var jss1 = jss.forDocument(document)
jss1.defaultSheet = jss1._createSheet()
var jss2 = jss.forDocument(document)
jss2.defaultSheet = jss2._createSheet()
jss2.set('#A', {
color: 'green'
})
jss1.set('#A', {
color: 'red'
})
</script>
I found out jss lazily creates its sheet. So if you want to ensure the order of the stylesheets, you need to create them up front with _createSheet.
I'm trying to apply CSS repeatedly and automatically to specific words.
For example, for the word "Twitter" I want the colour of the text to be #00ACED.
At present I am manually applying these colours around specific brand terms using span classes:
<span class="twitter">Twitter</span>
With the CSS:
.twitter {
color: #00ACED;
}
However, this is a process and I would prefer a method which completes this styling automatically. I have about 20 brand words with an associated colour styling.
Can anyone assist me with this problem. I am using WordPress if that makes any difference.
I think the most straight-forward way to do it is by using a smart jQuery highlight plugin I came across. After applying it, you'll be able to do what you're after. Below is an example, with a link to a live fiddle at the end:
HTML
<p>Some examples of how to highlight words with the jQuery Highlight plugin. First an example to demonstrate the default behavior and then others to demonstrate how to highlight the words Facebook and Twitter with their own class names. Words will be highlighted anywhere in the DOM, one needs only to be specific on where the script should look for the words. It supports case-sensitivity and other options, like in the case of YouTube.</p>
CSS
p { line-height: 30px; }
span { padding: 4px; }
.highlight { background-color: yellow; }
.facebook { background-color: #3c528f; color: white; }
.twitter { background-color: #1e9ae9; color: white; }
.youtube { background-color: #be0017; color: white; }
Highlight Plugin (needs to be loaded after jQuery and before the JavaScript below)
<script type="text/javascript" src="http://github.com/bartaz/sandbox.js/raw/master/jquery.highlight.js"></script>
JS
// default
$("body p").highlight("default");
// specify class name (not case sensitive)
$("body p").highlight("twitter", { className: 'twitter' });
$("body p").highlight("facebook", { className: 'facebook' });
// specify class name (case sensitive)
$("body p").highlight("YouTube", { className: 'youtube', caseSensitive: true });
Include this JavaScript at the bottom of the page (before the body closing tag so that you don't need to use the function below:
$(document).ready(function() {
// unnecessary if you load all your scripts at the bottom of your page
});
Fiddle for the win! :)
Something like this may work. You would have to loop through your search terms and this might not be the most effective way to do it.
function add_class (search, replacement) {
var all = document.getElementsByTagName("*");
for (var i=0, max=all.length; i < max; i++) {
var text = all[i].textContent || all[i].innerText;
if (text.indexOf(search) !== -1 && ! all[i].hasChildNodes()) {
all[i].className = all[i].className + " " + replacement;
}
}
}
var replacements = [
["Twitter","twitter"],
//
]
for (var i = replacements.length - 1; i >= 0; i--) {
add_class(replacements[i][0],replacements[i][1]);
};
Note: I didn't test this at all.
If you know minimum among of JavaScript, this JavaScript library can make your life much easier. it will convert all the letter in the string into a span tag. http://daverupert.com/2010/09/lettering-js/
For those of you interested in the answer, I've created a solution using WordPress functionality:
function replace_custom_word($text){
$replace = array(
'Twitter' => '<span class="twitter"><a title="Twitter" target="_blank" href="http://www.twitter.com/">Twitter</a></span>',
'Facebook' => '<span class="facebook"><a title="Facebook" target="_blank" href="http://www.facebook.com/">Facebook</a></span>'
);
$text = str_replace(array_keys($replace), $replace, $text);
return $text;}