What is RunHTML?
RunHTML is an online HTML runner and preview tool. Enter a complete HTML document, include CSS and JavaScript, and check the webpage result directly in your browser.
How do I run HTML code?
Enter or paste a complete HTML document in the editor and click Run preview. RunHTML creates a local Blob URL and opens the preview result in a new tab.
Can I use CSS and JavaScript together?
Yes. Put CSS in a style element and vanilla JavaScript in a script element so the document can run independently as a complete HTML page.
Is my code uploaded automatically?
No. Normal editing and previews happen in your browser, and the editor draft is kept locally. HTML is sent to the server only after you click Share and confirm.
What is the difference between a preview URL and a share link?
A preview uses a browser-generated local Blob URL for your own testing. A share link is generated by the server for others to open and is valid for only 1 hour.
How long does a share link last?
A share link is valid for 1 hour. After it expires, the shared file is automatically deleted and the link can no longer be opened.
Why is content reviewed before sharing?
A safety review helps reduce the spread of unlawful or non-compliant content. Before sharing, visible page text is extracted and reviewed. Political persuasion, pornography, violence, malware, fraud, and other non-compliant content will not receive a share link.
How do I clear or save my code?
Click Clear to remove the textarea content and save an empty draft. Use Copy to copy the complete HTML, or Download to save an HTML file with a timestamped filename.
Can I use RunHTML on a phone or tablet?
Modern phone and tablet browsers are supported. A larger screen or external keyboard is more comfortable for long code, and you may need to allow new tabs if the browser blocks the preview.