HTML Preview

How it works

You type, the iframe re-renders. The markup is handed to a <iframe srcDoc> with the sandbox attribute set to an empty string, the most restrictive setting. Scripts do not run, forms do not submit, popups do not open, and the frame cannot reach back into this page. Useful when you want to see what raw HTML looks like without trusting it.

When to use it

• Sketching a small HTML snippet for a blog or email.
• Inspecting a fragment you got from somewhere and don't trust yet.
• Teaching someone HTML without giving them a code editor.

If you need scripts to run inside the preview, the sandbox attribute is the place to loosen permissions, but do it deliberately, not by default.