JavaScript Diff Checker

Paste two versions of JavaScript code to compare additions, removals and edited lines with JavaScript syntax highlighting. The diff runs locally in your browser.

原始文字

修改後文字

JavaScript syntax locked

This page automatically highlights JavaScript tokens, so you do not need to pick a language before comparing files.

Private local compare

The diff runs in your browser. Source code, API payloads and configuration files are not uploaded to a server.

Split or unified review

Use split view for side-by-side review, unified view for compact patches, and hide unchanged lines for large files.

Compare JavaScript files online

This JavaScript diff checker is built for developers who need a fast, private way to compare code and configuration changes. Paste two versions, run the comparison, and review additions, removals and inline edits with JavaScript syntax highlighting already enabled.

Paste or upload the original JavaScript file on the left.
Paste or upload the changed JavaScript file on the right.
Compare the result in split or unified view, then hide unchanged lines when you only need the edited regions.

Private browser-based JavaScript comparison

The diff runs locally in your browser, which keeps source code, API responses, secrets and configuration files on your device. One recent session may be stored in your browser storage for restore, and you can clear it from the tool at any time.

Common JavaScript diff workflows

Compare functions, imports and component changes.

Review browser or Node.js edits before shipping.

Check object, array and async logic changes quickly.

JavaScript syntax highlighting

Highlighting is locked to JavaScript on this page, so the language selector stays out of the way. The parser focuses on tokens such as imports, functions, objects, async expressions while the diff engine highlights the actual text changes.

.js, .mjs, .cjs, .jsx

Reference: MDN JavaScript reference