Inline Math Evaluator (Chrome Extension)

Auto-completes math equations while you type in input and textarea fields. When the current line ends with = (equals followed by two spaces), it evaluates the expression on that line and replaces it inline with a single space around = plus one trailing space, placing the caret after that space.

• Only capital X is accepted for multiplication (by design, due to formatting constraints).
• Supports +, -, * (via X), /, parentheses, unary plus/minus, and % as a literal (e.g., 10% → 0.1).
• Detects mismatched parentheses and invalid expressions.

Install (Developer Mode)

1. Download or clone this folder locally.
2. Open Chrome and go to chrome://extensions.
3. Toggle on "Developer mode" (top-right).
4. Click "Load unpacked" and select this project folder.
5. The extension will appear in your extensions list.

Usage

• In any website with a text field (input or textarea), type an expression on a line such as:
  • 5 X 3 = → becomes 5 X 3 = 15 ␠ (caret moves to the end, after one trailing space)
  • -(2 + 3) = → becomes -(2 + 3) = -5 ␠
  • 2 + (-3) = → becomes 2 + (-3) = -1 ␠
• Multiple expressions in a single line are supported. The extension evaluates only the segment after the last = before the trigger and preserves earlier results. Example:
  • Type: 5 X 5 = → becomes 5 X 5 = 25 ␠
  • Continue typing: X 4 = on the same line → becomes 5 X 5 = 25 X 4 = 100 ␠
• Trigger condition: the line must end with = (exactly two spaces after =). Other triggers are ignored by design.

Files

• manifest.json: Chrome Extension Manifest V3 configuration.
• background.js: Minimal background service worker (MV3), currently logs installation.
• content.js: The content script that performs inline evaluation.

Constraints and Notes

• Multiplication: Only capital X works (e.g., 5 X 3). Lowercase x, ×, or * are not accepted as input; only X is recognized and internally mapped to * for evaluation.
• Percentage semantics: Currently 10% is interpreted as 0.1 (a literal). If you want "percent of previous term" semantics (e.g., 50 + 10% → 55), we can add that later.
• Locales: No locale-specific number formatting.
• Targets: Works only on input and textarea fields (not contenteditable).
• Safety: Runs broadly on pages. If you need to restrict it, we can add host filters or input type checks.

Troubleshooting

• If nothing happens, ensure the line ends with = (equals followed by two spaces) and that your caret is on that line.
• If you see "Invalid expression", check for:
  • Mismatched parentheses
  • Disallowed characters
  • Divide by zero
• If you’re testing on file:// pages, enable "Allow access to file URLs" for this extension in chrome://extensions.

Development

• Edit content.js to adjust behavior. Reload the extension via chrome://extensions → "Reload".
• Open DevTools (F12) on any page, check the Console for logs/errors from the content script.
• Background logs appear in chrome://extensions → click "service worker" link under this extension.

License

MIT