# Mobile Autocomplete Fix

**Date:** 2026-03-28
**File changed:** `static/toolbar.js`

## The Problem

On mobile, typing in the terminal caused glitchy re-typing of characters. For example, typing `git sta` would suddenly delete and re-insert text, producing garbled input like `git stagit sta`.

## Root Cause

xterm.js captures keyboard input through a hidden `<textarea>` element (class: `.xterm-helper-textarea`). Mobile browsers (iOS Safari, Android Chrome/Gboard) treat this like any other text field and activate autocomplete, autocorrect, autocapitalize, and spellcheck.

When the keyboard's autocomplete activates, it:

1. Deletes the characters you already typed (sends backspace events)
2. Re-inserts the "corrected" or "completed" word

xterm.js interprets this as real input — backspaces erase terminal content, then the replacement text gets typed out. The result is duplicated or garbled text visible on screen.

## The Fix

A `disableMobileAutocomplete()` function finds xterm's hidden textarea and sets four attributes that suppress mobile keyboard text assistance:

```javascript
ta.setAttribute('autocomplete','off');    // Chrome, general
ta.setAttribute('autocorrect','off');     // Safari
ta.setAttribute('autocapitalize','off');  // iOS (prevents auto-capitalizing first letter)
ta.setAttribute('spellcheck','false');    // All browsers (removes red underlines + suggestions)
```

All four are needed because different browsers respect different attributes.

## Why a MutationObserver

The hidden textarea doesn't exist at page load — xterm.js creates it dynamically when the terminal mounts. The existing `MutationObserver` (which already handles mobile toolbar resizing) now also calls `disableMobileAutocomplete()` on every DOM change. A `data-acOff` guard ensures the attributes are only set once.

## Nuclear Option (if still broken)

Some aggressive keyboards (Samsung Keyboard, certain Gboard versions) may ignore these attributes entirely. If that happens, setting `inputMode="none"` on the textarea would fully disable the soft keyboard — but that requires adding a separate on-screen keyboard or toggle, since users would lose the ability to type normally.