From plain text to semantic HTML
Converting plain text to HTML involves more than just wrapping lines in <p> tags. Our converter applies semantic HTML: headings (h1-h6), lists (ul/ol), tables, blockquotes, and code blocks are detected from common plain-text conventions. The tool respects single vs double line breaks: a single newline within a paragraph becomes a <br> (or is ignored), while double newlines create a new paragraph. This mirrors how Markdown and most WYSIWYG editors handle line breaks.
For accessibility, the generated HTML includes proper heading hierarchy (no skipping levels), alt text placeholders for detected image references, and ARIA labels for navigation-like structures. The output also includes a data-schema attribute that identifies the structural role of each section (article, navigation, complementary) for screen readers.
Security: preventing XSS in generated HTML
Converting user-provided text to HTML carries XSS risks if the input contains malicious HTML or JavaScript. Our tool sanitizes all output by encoding angle brackets (< >), ampersands (&), and quote characters. If the input appears to contain HTML tags, the tool offers a "passthrough" mode that preserves existing HTML while formatting the rest. By default, the tool operates in safe mode: all tags are escaped, and only structural formatting is applied. Never render user-generated HTML without additional server-side sanitization — a DOMPurify pass on the server is strongly recommended.
The tool also normalizes URLs in detected links: href attributes are prefixed with https:// if no protocol is present (preventing javascript: injection), and mailto: links are encoded to protect against email harvesters.