HTML5: How to specify the legal number intervals for an input field?

Last update on February 09 2024 12:52:40 (UTC/GMT +8 hours)

Solution:

HTML Code:

<!DOCTYPE html><!-- Declares the document type and version of HTML -->
<html>
<head>
<meta charset="utf-8"><!-- Specifies the character encoding for the document -->
<title>How to specify the legal number intervals for an input field</title><!-- Sets the title of the document -->
</head>
<body>
<form method="post" <!-- Begins a form element with the method attribute set to "post", indicating that form data will be submitted via HTTP POST method -->
action="https://www.w3resource.com/html-css-exercise/basic/solution/input-step-answer-demo.php"><!-- Specifies the URL where the form data will be sent upon submission -->
 Input a number: <input type="number" <!-- Creates a number input field for entering a number. The name attribute is set to "points" to identify the input data on the server side -->
name="points" step="2"><!-- Specifies the legal number intervals for the input field. In this case, it allows only numbers that are multiples of 2 -->
<input type="submit"><!-- Creates a submit button within the form -->
</form>
</body>
</html>

Explanation:

The HTML document starts with a declaration of its type and version (<!DOCTYPE html>).
The <html> element encloses the entire HTML document.
The <head> section contains metadata about the document, including the character encoding (<meta charset="utf-8">) and the title of the document (<title>).
Within the <body> section, a <form> element is used to create a form for user input. The method attribute is set to "post", indicating that form data will be submitted via HTTP POST method, and the action attribute specifies the URL where the form data will be sent upon submission.
Inside the form, there's an <input> element with type "number" for entering a number. The name attribute is set to "points" to identify the input data on the server side.
The input field also includes the step attribute, which specifies the legal number intervals for the input field. In this case, it's set to "2", meaning only numbers that are multiples of 2 will be allowed.
Finally, an <input> element with type "submit" is used to create a submit button within the form, allowing users to submit the form data.

Live Demo:

See the Pen input-step-answer by w3resource (@w3resource) on CodePen.

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