Why Unclosed HTML Tags Break Your Layout
Browsers try to self-heal broken HTML, but the recovery is unpredictable — what looks fine in Chrome may collapse in Safari or show broken layout in emails and CMS previews.
The silent layout killer
A missing </div> inside a CMS template can push your footer into the sidebar or collapse an entire section — with zero error messages in the browser console.
Void vs non-void tags
Tags like <br>, <img>, <input> are void — they can't have children and don't need closing. Writing <br/> is fine in XHTML; plain <br> is correct in HTML5.
Nesting rules matter
You can't put a <div> inside a <p> — the browser will auto-close the <p> first, breaking your intended structure. Inline inside block is fine; block inside inline is not.
Email HTML is stricter
Email clients don't self-heal like browsers. An unclosed <td> or <table> in an email template will render completely differently across Gmail, Outlook, and Apple Mail.
Deprecated tags still work — for now
Tags like <center>, <font>, <marquee> still render but are removed from the spec. Browsers can drop support any release. Migrate to CSS equivalents.
Auto-fix caveats
Auto-fix is safe for standard HTML. For complex templates with server-side tags ({% %}, <?php ?>), always review the diff — template syntax can confuse parsers.