Source
Paste HTML
Ready to inspect HTML.
Developer utility
HTML Viewer
Preview and inspect HTML in a script-disabled sandbox, compare source and sanitized markup, extract readable text, and review document structure without uploading code.
Paste HTML to render and inspect its document structure.
Source size0 B
Elements0
Headings0
Links0
Removed or changed items: 0
Sandboxed output
HTML preview
The iframe has no script, form, popup, same-origin, or top-navigation permission. Source mode can preserve markup, but the sandbox still blocks script execution.
Processed markup
HTML sent to the preview
Document checks
HTML warnings and sanitization report
Paste HTML to render and inspect its document structure.
DOM outline
Element summary
| Element | Count | IDs / classes | First text |
|---|---|---|---|
| No body elements detected. | |||
Readable content
Extracted text
Examples
HTML preview samples
HTML preview safety reference
| Content | Sanitized mode | Source mode |
|---|---|---|
| HTML elements and text | Rendered | Rendered |
| Inline CSS | Kept after dangerous imports and URLs are removed | Kept inside the sandbox |
| Script elements | Removed | Preserved but blocked |
| Inline event handlers | Removed | Preserved but blocked |
| iframe, object, embed | Removed | Restricted by the sandbox |
| Network resources | Blocked by default with CSP and attribute cleanup | Allowed only when network blocking is disabled |
HTML Viewer FAQ
Can pasted JavaScript run in the preview?
No. The iframe has no script permission. Sanitized mode also removes scripts, embedded frames, inline event handlers, dangerous URLs, and active navigation directives.
Does HTML leave my browser?
No. Parsing, sanitization, preview rendering, text extraction, document statistics, and downloads run locally. Network references are blocked by default.
Why can the preview differ from my production site?
The sandbox has no access to your site's runtime, cookies, same-origin APIs, or server routes. Network resources remain unavailable unless you explicitly disable blocking.
Is this a complete HTML validator?
No. It provides practical structure, accessibility, duplicate-ID, heading-order, image-alt, and safety checks. Standards conformance still requires a dedicated validator.