A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_URI::$config is deprecated
Filename: core/URI.php
Line Number: 102
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Router::$uri is deprecated
Filename: core/Router.php
Line Number: 128
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$benchmark is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$hooks is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$config is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$log is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$utf8 is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$uri is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$exceptions is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$router is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$output is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$security is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$input is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$lang is deprecated
Filename: core/Controller.php
Line Number: 83
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$db is deprecated
Filename: core/Loader.php
Line Number: 397
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_DB_mysqli_driver::$failover is deprecated
Filename: database/DB_driver.php
Line Number: 372
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$email is deprecated
Filename: core/Loader.php
Line Number: 1284
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 303
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: session_set_cookie_params(): Session cookie parameters cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 328
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 355
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 365
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 366
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 367
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 368
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: ini_set(): Session ini settings cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 426
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: session_set_save_handler(): Session save handler cannot be changed after headers have already been sent
Filename: Session/Session.php
Line Number: 110
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: Warning
Message: session_start(): Session cannot be started after headers have already been sent
Filename: Session/Session.php
Line Number: 137
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$session is deprecated
Filename: core/Loader.php
Line Number: 1284
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$form_validation is deprecated
Filename: core/Loader.php
Line Number: 1284
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$pagination is deprecated
Filename: core/Loader.php
Line Number: 1284
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property Blog::$zip is deprecated
Filename: core/Loader.php
Line Number: 1284
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$load is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$benchmark is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$hooks is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$config is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$log is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$utf8 is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$uri is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$exceptions is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$router is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$output is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$security is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$input is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$lang is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$db is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$email is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$session is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$form_validation is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$pagination is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
A PHP Error was encountered
Severity: 8192
Message: Creation of dynamic property CI_Loader::$zip is deprecated
Filename: core/Loader.php
Line Number: 932
Backtrace:
File: /www/wwwroot/SINHCOMS/VT/main/application/controllers/Blog.php
File: /www/wwwroot/SINHCOMS/VT/main/index.php
Vismrit Tech | Home Startup
Theresa Underwood
Sep 10, 2021
9 min to read
The class attribute is often used to point to a class name in a style sheet. It can also be used by a JavaScript to access and manipulate elements with the specific class name.
CSS classes are commonly used to define a set of CSS styles and then apply them on an HTML element using selectors. To define a class within a CSS stylesheet, use the dot selector, as follows:
<style>
.nice {
font-family: sans-serif;
}
</style>
Each HTML element can have a set of classes, ordered in a specific order. Each class will potentially add a set of CSS definitions according to the styles that were defined in the page. In this piece of code we have defined a CSS rule that will be applied to every element that contains the "nice" class. This means that once this piece of code has been defined inside the HTML page, the following HTML paragraph will have the style applied to it:
<style>
.nice {
font-family: sans-serif;
}
</style>
<p class="nice">This is a short sentence.</p>
HTML5 classList API HTML5 introduced a new way to edit the class list of an element using the classList collection. Each HTML element returns the collection by accessing the element.classList member. The class list allows to add, remove, toggle and to check if an element contains a specific class.
Let's see an example:
<!DOCTYPE html>
<html>
<head>
<style>
.nice {
font-family: sans-serif;
}
</style>
</head>
<body>
<p id="mytext">My text</p>
<script>
var el = document.getElementById("mytext");
el.classList.add("nice"); // adds the nice class to the paragraph
el.classList.remove("nice"); // removes the nice class from the paragraph
el.classList.toggle("nice"); // adds the nice class to the paragraph again, since it does not currently
// contain the nice class.
if (el.classList.contains("nice")) {
alert("The element contains the 'nice' class.");
}
</script>
</body>
</html>
Since HTML5 is a relatively new standard, it is not supported on all browsers. It is safe enough to use today though. Here is the compatibility table for the feature: http://caniuse.com/#search=classlist
Exercise This page does not have an exercise yet. You are welcome to contribute one by sending me a pull request:
https://github.com/ronreiter/interactive-tutorials
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