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Input Validation Playground

Compare safe vs unsafe input handling. Learn why encoding/escaping matters.

⚠️ Educational Purpose: This tool demonstrates why proper input validation and encoding is crucial. It does not exploit real applications.

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Unsafe (innerHTML)

Using innerHTML directly renders HTML/JavaScript, allowing XSS attacks.

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Safe (textContent)

Using textContent escapes HTML, preventing XSS attacks.

Best Practices:

  • ✅ Use textContent: For user-generated text, always use textContent instead of innerHTML.
  • ✅ Escape HTML: If you must use HTML, escape special characters (<, >, &, ", ').
  • ✅ Validate Input: Validate and sanitize all user input on both client and server side.
  • ✅ Use Trusted Libraries: Use libraries like DOMPurify to sanitize HTML before rendering.
  • ✅ Content Security Policy: Implement CSP headers to prevent XSS attacks at the browser level.

Input Validation Playground – Learn XSS Prevention

Cross-Site Scripting (XSS) is one of the most common web security vulnerabilities. It occurs when malicious scripts are injected into web pages and executed in users' browsers. Understanding how to prevent XSS attacks is crucial for web developers. The Input Validation Playground by ToolfolioHub demonstrates safe versus unsafe input handling, showing exactly why proper validation and encoding matter.

This educational tool compares `innerHTML` (unsafe) with `textContent` (safe) side-by-side, making it clear why input validation is essential for web security.

What is XSS (Cross-Site Scripting)?

XSS attacks occur when attackers inject malicious scripts into web pages:

  • Stored XSS: Malicious scripts stored in database and displayed to users
  • Reflected XSS: Scripts reflected in URL parameters or form submissions
  • DOM-based XSS: Scripts executed through DOM manipulation

These attacks can steal cookies, hijack sessions, deface websites, or redirect users to malicious sites.

Safe vs Unsafe Input Handling

Unsafe: innerHTML

Using `innerHTML` directly renders HTML and executes JavaScript:

  • HTML tags are interpreted as markup
  • JavaScript in `