Filtration in the context of HTML, JavaScript (JS), and CSS refers to the process of cleaning or sanitizing code to remove unwanted, unsafe, or redundant elements. This may include removing:
Malicious scripts (e.g. XSS payloads),
Unused styles or code,
Invalid or deprecated tags or attributes,
Code that violates security or performance best practices.
It is often used to protect applications or optimize codebases.
Security: Prevents malicious code injection (e.g., XSS attacks in HTML/JS).
Optimization: Removes unused or redundant code to reduce file size and speed up load time.
Compliance: Ensures only valid and safe code is processed or stored.
Clean Input Handling: Useful when users submit HTML/JS content (e.g., in CMSs or WYSIWYG editors).
Online Tools: Paste code into a filtration tool to clean or sanitize it.
Sanitization Libraries: Use libraries like DOMPurify (HTML/JS), PurifyCSS or UnCSS (CSS), or content security filters in your backend (e.g., OWASP rules).
Code Linters/Analyzers: Tools like ESLint (JS), Stylelint (CSS), or HTMLHint help detect and remove problematic code patterns.
Frameworks and CMS Plugins: Many content platforms offer built-in or plugin-based filtration tools for user-generated content.
When accepting user-generated content that could include HTML or script.
During code cleanup, especially in legacy projects or after copying/pasting from external sources.
Before deploying a site or application to ensure clean, safe, and efficient code.
When scraping, parsing, or importing third-party content that may contain unwanted or unsafe elements.