What HTML Tags Are Not Supported in Emails?
Understanding email client compatibility and HTML tag support
Table of Contents
What HTML Tags Are Not Supported in Emails?
Many HTML tags are not supported in emails due to email client limitations and security restrictions. Unsupported tags include JavaScript tags (<script>, <iframe>), interactive elements (<form>, <input>, <button>), modern HTML5 tags (<video>, <audio>, <canvas>), CSS3 features (animations, flexbox, grid), and certain styling tags (<style> in body).
Email clients strip unsupported tags for security and compatibility reasons. Use table-based layouts, inline styles, and email client-compatible HTML instead. Validate HTML using our HTML validator and test emails in multiple clients to ensure compatibility.
Understanding unsupported tags helps create email HTML that renders correctly across email clients.
JavaScript Tags
Script Tags
JavaScript tags (<script>) are not supported in emails for security reasons. Email clients strip JavaScript to prevent malicious code execution.
Iframe Tags
<iframe> tags are not supported in emails. Email clients block iframes for security reasons.
Event Handlers
Inline event handlers (onclick, onload, etc.) are not supported or are stripped by email clients.
Security Reasons
JavaScript and iframes are blocked to prevent security vulnerabilities, malicious code execution, and phishing attacks.
Interactive Elements
Form Elements
Form elements (<form>, <input>, <button>, <select>) are not supported in emails. Email clients strip forms for security reasons.
Input Types
All input types are unsupported, including text, email, password, checkbox, radio, and file inputs.
Button Elements
<button> tags are often stripped. Use <a> tags styled as buttons instead.
Alternative Approaches
Use links to landing pages with forms instead of embedding forms in emails.
Modern HTML5 Tags
Media Tags
Modern HTML5 media tags (<video>, <audio>, <canvas>) are not supported in emails. Email clients don't support embedded media.
Semantic Tags
Many HTML5 semantic tags (<section>, <article>, <nav>, <header>, <footer>) may not be supported or render inconsistently.
HTML5 Features
HTML5 features like data attributes, contenteditable, and other modern features are not supported in emails.
Compatibility
Use traditional HTML4 and table-based layouts for maximum email client compatibility.
CSS Features
External Stylesheets
External stylesheets (<link> tags) are not supported. Email clients strip external CSS references.
Style Tags in Body
<style> tags in the email body are often stripped. Use inline styles instead.
CSS3 Features
CSS3 features like animations, transitions, flexbox, grid, and advanced selectors are not supported or render inconsistently.
Best Practice
Use inline styles and table-based layouts for consistent email rendering across clients.
Email HTML Best Practices
1. Use Table-Based Layouts
Use HTML tables for layout instead of CSS-based layouts for maximum email client compatibility.
2. Use Inline Styles
Use inline styles instead of external stylesheets or style tags for consistent rendering.
3. Avoid Unsupported Tags
Avoid JavaScript, forms, iframes, and modern HTML5 tags that aren't supported in emails.
4. Test in Multiple Clients
Test emails in multiple email clients to ensure compatibility and proper rendering.
5. Validate HTML
Use our HTML validator to identify unsupported tags and validate email HTML.
6. Follow Email Standards
Follow email HTML standards and best practices for maximum compatibility across email clients.
