HTML Program to Input Patterns with Explanation
HTML
Medium
HTML Forms
27 views
1 min read
81 words
This problem helps you practice core HTML fundamentals in a practical way. It builds intuition around pattern, html, code. Let’s break it down step by step so you can implement it confidently.
Problem Statement
Create a username input that allows only letters and numbers (pattern).
Input Format
No input.
Output Format
Print the HTML code.
Constraints
Use pattern attribute.
Code Solution
This explanation is written for learning purposes and to help beginners understand the concept clearly.
<!doctype html>
<html lang='en'>
<head>
<meta charset='utf-8'>
<meta name='viewport' content='width=device-width, initial-scale=1'>
<title>meetcode</title>
</head>
<body>
<form action='#' method='post'>
<label>Username
<input type='text' name='username' pattern='[A-Za-z0-9]+' required>
</label>
<button type='submit'>Save</button>
</form>
</body>
</html>
Output Example
No sample I/O is provided for this question.
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Solution Guide
Problem
Create a username input that allows only letters and numbers (pattern).
Input / Output
Output
Print the HTML code.
Constraints
Use pattern attribute.
Details
Common Mistakes
- Misreading input/output format.
- Not handling constraints and edge cases.
- Off-by-one errors in loops.
- Forgetting to reset variables between test cases (if any).
Official Solution
<!doctype html>
<html lang='en'>
<head>
<meta charset='utf-8'>
<meta name='viewport' content='width=device-width, initial-scale=1'>
<title>meetcode</title>
</head>
<body>
<form action='#' method='post'>
<label>Username
<input type='text' name='username' pattern='[A-Za-z0-9]+' required>
</label>
<button type='submit'>Save</button>
</form>
</body>
</html>
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