HTML BLOCK & INLINE, HTML CLASSES & HTML ID
Hello guys myself Harshith.G.B. Today we are going to continue our journey of learning HTML. Today we will be learning 3 more topics, that are :
HTML block & inline
HTML classes
HTML id
HTML block & inline
Every HTML element has a default display value, depending on what type of element it is. There are two display values: block & inline.
Block-level elements
A block-level element always starts on a new line, and the browsers automatically add some space (a margin) before and after the element. A block-level element always takes up the full width available (stretches out to the left and right as far as it can). Two commonly used block elements are: <p> and <div>. The <p> element defines a paragraph in an HTML document. The <div> element defines a division or a section in an HTML document.
Example :
<p>Hello World</p>
<div>Hello World</div>
Inline elements
An inline element does not start on a new line. An inline element only takes up as much width as necessary. The <span> element is an inline element.
Example :
<span>Hello World</span>
Note: An inline element cannot contain a block-level element!
HTML classes
The HTML class attribute is used to specify a class for an HTML element. Multiple HTML elements can share the same class.
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. In the following example we have three <div> elements with a class attribute with the value of "city". All of the three <div> elements will be styled equally according to the .city style definition in the head section.
Example :
<!DOCTYPE html>
<html>
<head>
<style>
.city {
background-color: tomato;
color: white;
border: 2px solid black;
margin: 20px;
padding: 20px;
}
</style>
</head>
<body>
<div class="city">
<h2>London</h2>
<p>London is the capital of England.</p>
</div>
<div class="city">
<h2>Paris</h2>
<p>Paris is the capital of France.</p>
</div>
<div class="city">
<h2>Tokyo</h2>
<p>Tokyo is the capital of Japan.</p>
</div>
</body>
</html>
In the following example we have two <span> elements with a class attribute with the value of "note". Both <span> elements will be styled equally according to the .note style definition in the head section.
Example :
<!DOCTYPE html>
<html>
<head>
<style>
.note {
font-size: 120%;
color: red;
}
</style>
</head>
<body>
<h1>My <span class="note">Important</span> Heading</h1>
<p>This is some <span class="note">important</span> text.</p>
</body>
</html>
Tip: The class attribute can be used on any HTML element.
Note: The class name is case sensitive!
The syntax for class
To create a class; write a period (.) character, followed by a class name. Then, define the CSS properties within curly braces {}To create a class; write a period (.) character, followed by a class name. Then, define the CSS properties within curly braces {}.
Example :
<!DOCTYPE html>
<html>
<head>
<style>
.city {
background-color: tomato;
color: white;
padding: 10px;
}
</style>
</head>
<body>
<h2 class="city">London</h2>
<p>London is the capital of England.</p>
<h2 class="city">Paris</h2>
<p>Paris is the capital of France.</p>
<h2 class="city">Tokyo</h2>
<p>Tokyo is the capital of Japan.</p>
</body>
</html>
Multiple classes
HTML elements can belong to more than one class. To define multiple classes, separate the class names with a space, e.g. <div class="city main">. The element will be styled according to all the classes specified. In the following example, the first <h2> element belongs to both the city class and also to the main class, and will get the CSS styles from both of the classes.
Example :
<h2 class="city main">London</h2>
<h2 class="city">Paris</h2>
<h2 class="city">Tokyo</h2>
HTML id
The HTML id attribute is used to specify a unique id for an HTML element. You cannot have more than one element with the same id in an HTML document.
Using the id attribute
The id attribute specifies a unique id for an HTML element. The value of the id attribute must be unique within the HTML document. The id attribute is used to point to a specific style declaration in a style sheet. It is also used by JavaScript to access and manipulate the element with the specific id. The syntax for id is: write a hash character (#), followed by an id name. Then, define the CSS properties within curly braces {}. In the following example we have an <h1> element that points to the id name "myHeader". This <h1> element will be styled according to the #myHeader style definition in the head section.
Example :
<!DOCTYPE html>
<html>
<head>
<style>
#myHeader {
background-color: lightblue;
color: black;
padding: 40px;
text-align: center;
}
</style>
</head>
<body>
<h1 id="myHeader">My Header</h1>
</body>
</html>
Note: The id name is case sensitive! The id name must contain at least one character, cannot start with a number, and must not contain whitespaces (spaces, tabs, etc.).
Difference between class & id
A class name can be used by multiple HTML elements, while an id name must only be used by one HTML element within the page.
Example :
<style>
/* Style the element with the id "myHeader" */
#myHeader {
background-color: lightblue;
color: black;
padding: 40px;
text-align: center;
}
/* Style all elements with the class name "city" */
.city {
background-color: tomato;
color: white;
padding: 10px;
}
</style>
<!-- An element with a unique id -->
<h1 id="myHeader">My Cities</h1>
<!-- Multiple elements with same class -->
<h2 class="city">London</h2>
<p>London is the capital of England.</p>
<h2 class="city">Paris</h2>
<p>Paris is the capital of France.</p>
<h2 class="city">Tokyo</h2>
<p>Tokyo is the capital of Japan.</p>