Userscript API Benchmark

Purpose

This script is a comprehensive benchmark tool designed to test the compatibility and accuracy of Userscript Manager APIs. It verifies whether the APIs (both GM_* and GM.*) are correctly implemented according to the standards (e.g., Tampermonkey documentation).

It is particularly useful for:

• Developers: To verify if their userscript manager supports required APIs.
• Users: To check the capabilities of their installed userscript manager.
• Maintainers: To audit compliance with GM standards, especially for newer asynchronous GM.* APIs.

Features

• Dual API Support: Tests both legacy synchronous GM_* APIs and modern asynchronous GM.* APIs.
• Type Verification: Checks if synchronous APIs return values directly and asynchronous APIs return Promises.
• Functional Testing: Executes actual API calls (e.g., storage read/write, value change listeners) to verify functionality, not just existence.
• Isolated Execution: Ensures that a failure in one API test does not block the execution of others.
• Visual Reporting: Displays a clear, color-coded table of results (Pass/Fail/N/A) directly on the page.

Usage

1. Install the script in your Userscript Manager (Tampermonkey, Violentmonkey, etc.).
2. Visit any webpage.
3. Open the Userscript Manager menu.
4. Click on "Run Benchmark".
5. A table will appear overlaying the page with the test results.

• Install link: https://github.com/utags/userscript-api-benchmark/raw/refs/heads/main/userscript-api-benchmark.user.js
• Copy results: Click "Copy" to get results in Markdown format.
• Submit results: https://github.com/utags/userscript-api-benchmark/issues

API Docs

• Tampermonkey: https://www.tampermonkey.net/documentation.php
• Violentmonkey: https://violentmonkey.github.io/api/gm/
• ScriptCat: https://docs.scriptcat.org/docs/dev/api/
• Greasemonkey: https://wiki.greasespot.net/Greasemonkey_Manual:API
• Userscripts: https://github.com/quoid/userscripts

Benchmark Results

Tampermonkey

• Manager: Tampermonkey (5.4.1)
• Browser: Chrome 143.0.0.0
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	✅	1/1	✅	1/1
setValue / getValue	✅	3/3	✅	3/3
deleteValue	✅	1/1	✅	1/1
listValues	✅	1/1	✅	1/1
setValues / getValues / deleteValues	✅	1/1	✅	1/1
addValueChangeListener / removeValueChangeListener	✅	5/5	✅	5/5
addStyle	✅	1/1	✅	1/1
addElement	✅	6/6	✅	6/6
registerMenuCommand	✅	1/1	✅	1/1
unregisterMenuCommand	✅	1/1	✅	1/1
xmlHttpRequest	✅	1/1	✅	1/1
download	✅	1/1	✅	1/1
openInTab	✅	1/1	✅	1/1
setClipboard	✅	1/1	✅	1/1
notification	✅	1/1	✅	1/1
getResourceText	✅	1/1	✅	1/1
getResourceURL	✅	1/1	✅	1/1
getTab / saveTab / getTabs	✅	1/1	✅	1/1
cookie	✅	1/1	✅	1/1
audio	✅	1/1	✅	1/1
webRequest (Deprecated)	✅	1/1	✅	1/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	✅	1/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

Violentmonkey

• Manager: Violentmonkey (2.31.0)
• Browser: Firefox 146.0
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	✅	1/1	✅	1/1
setValue / getValue	✅	3/3	✅	3/3
deleteValue	✅	1/1	✅	1/1
listValues	✅	1/1	✅	1/1
setValues / getValues / deleteValues	✅	1/1	✅	1/1
addValueChangeListener / removeValueChangeListener	✅	5/5	✅	5/5
addStyle	✅	1/1	✅	1/1
addElement	✅	6/6	✅	6/6
registerMenuCommand	✅	1/1	✅	1/1
unregisterMenuCommand	✅	1/1	✅	1/1
xmlHttpRequest	✅	1/1	✅	1/1
download	✅	1/1	✅	1/1
openInTab	✅	1/1	✅	1/1
setClipboard	✅	1/1	✅	1/1
notification	✅	1/1	✅	1/1
getResourceText	✅	1/1	✅	1/1
getResourceURL	✅	1/1	✅	1/1
getTab / saveTab / getTabs	❌	0/1	❌	0/1
cookie	❌	0/1	❌	0/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

ScriptCat

• Manager: ScriptCat (1.2.3)
• Browser: Chrome 143.0.0.0
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	✅	1/1	✅	1/1
setValue / getValue	⚠️	2/3	⚠️	2/3
deleteValue	✅	1/1	✅	1/1
listValues	✅	1/1	✅	1/1
setValues / getValues / deleteValues	✅	1/1	✅	1/1
addValueChangeListener / removeValueChangeListener	✅	5/5	✅	5/5
addStyle	✅	1/1	✅	1/1
addElement	✅	6/6	✅	6/6
registerMenuCommand	✅	1/1	✅	1/1
unregisterMenuCommand	✅	1/1	✅	1/1
xmlHttpRequest	✅	1/1	✅	1/1
download	✅	1/1	✅	1/1
openInTab	✅	1/1	✅	1/1
setClipboard	✅	1/1	✅	1/1
notification	✅	1/1	✅	1/1
getResourceText	✅	1/1	✅	1/1
getResourceURL	✅	1/1	✅	1/1
getTab / saveTab / getTabs	✅	1/1	✅	1/1
cookie	✅	1/1	✅	1/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

Userscripts (Safari)

• Manager: Userscripts (4.8.2)
• Browser: Safari 605.1.15
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	❌	0/1	❌	0/1
setValue / getValue	✅	3/3	❌	0/3
deleteValue	✅	1/1	❌	0/1
listValues	✅	1/1	❌	0/1
setValues / getValues / deleteValues	❌	0/1	❌	0/1
addValueChangeListener / removeValueChangeListener	❌	0/5	❌	0/5
addStyle	⚠️	0/1	❌	0/1
addElement	❌	0/6	❌	0/6
registerMenuCommand	❌	0/1	❌	0/1
unregisterMenuCommand	❌	0/1	❌	0/1
xmlHttpRequest	✅	1/1	✅	1/1
download	❌	0/1	❌	0/1
openInTab	✅	1/1	❌	0/1
setClipboard	✅	1/1	❌	0/1
notification	❌	0/1	❌	0/1
getResourceText	❌	0/1	❌	0/1
getResourceURL	❌	0/1	❌	0/1
getTab / saveTab / getTabs	❌	0/1	❌	0/1
cookie	❌	0/1	❌	0/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	❌	0/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

Stay (Safari)

• Manager: tamp (2.9.12)
• Browser: Safari 605.1.15
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	✅	1/1	✅	1/1
setValue / getValue	⚠️	2/3	⚠️	2/3
deleteValue	✅	1/1	✅	1/1
listValues	✅	1/1	✅	1/1
setValues / getValues / deleteValues	❌	0/1	❌	0/1
addValueChangeListener / removeValueChangeListener	⚠️	0/5	⚠️	0/5
addStyle	⚠️	0/1	✅	1/1
addElement	⚠️	4/6	⚠️	4/6
registerMenuCommand	✅	1/1	✅	1/1
unregisterMenuCommand	✅	1/1	✅	1/1
xmlHttpRequest	✅	1/1	✅	1/1
download	❌	0/1	✅	1/1
openInTab	✅	1/1	✅	1/1
setClipboard	✅	1/1	✅	1/1
notification	✅	1/1	✅	1/1
getResourceText	❌	0/1	✅	1/1
getResourceURL	✅	1/1	✅	1/1
getTab / saveTab / getTabs	✅	1/1	✅	1/1
cookie	✅	1/1	✅	1/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

Stay (Chrome)

• Manager: extensions/stay (0.1)
• Browser: Chrome 143.0.0.0
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	✅	1/1	✅	1/1
setValue / getValue	⚠️	2/3	⚠️	2/3
deleteValue	✅	1/1	✅	1/1
listValues	✅	1/1	✅	1/1
setValues / getValues / deleteValues	❌	0/1	❌	0/1
addValueChangeListener / removeValueChangeListener	⚠️	0/5	⚠️	0/5
addStyle	✅	1/1	✅	1/1
addElement	⚠️	4/6	⚠️	4/6
registerMenuCommand	✅	1/1	✅	1/1
unregisterMenuCommand	✅	1/1	✅	1/1
xmlHttpRequest	✅	1/1	✅	1/1
download	❌	0/1	✅	1/1
openInTab	✅	1/1	✅	1/1
setClipboard	✅	1/1	✅	1/1
notification	✅	1/1	✅	1/1
getResourceText	❌	0/1	✅	1/1
getResourceURL	✅	1/1	✅	1/1
getTab / saveTab / getTabs	✅	1/1	✅	1/1
cookie	✅	1/1	✅	1/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

Greasemonkey

• Manager: Greasemonkey (4.13)
• Browser: Firefox 146.0
• Date: 2025-12-30

API	GM.* (Support)	GM.* (Pass)	GM_* (Support)	GM_* (Pass)
info	✅	1/1	✅	1/1
log	❌	0/1	❌	0/1
setValue / getValue	✅	3/3	❌	0/3
deleteValue	✅	1/1	❌	0/1
listValues	✅	1/1	❌	0/1
setValues / getValues / deleteValues	❌	0/1	❌	0/1
addValueChangeListener / removeValueChangeListener	❌	0/5	❌	0/5
addStyle	❌	0/1	❌	0/1
addElement	❌	0/6	❌	0/6
registerMenuCommand	✅	1/1	❌	0/1
unregisterMenuCommand	❌	0/1	❌	0/1
xmlHttpRequest	✅	1/1	❌	0/1
download	❌	0/1	❌	0/1
openInTab	✅	1/1	❌	0/1
setClipboard	✅	1/1	❌	0/1
notification	✅	1/1	❌	0/1
getResourceText	❌	0/1	❌	0/1
getResourceURL	✅	1/1	❌	0/1
getTab / saveTab / getTabs	❌	0/1	❌	0/1
cookie	❌	0/1	❌	0/1
audio	❌	0/1	❌	0/1
webRequest (Deprecated)	❌	0/1	❌	0/1
unsafeWindow	✅	1/1	-	-
window.onurlchange	❌	0/1	-	-
window.close	✅	1/1	-	-
window.focus	✅	1/1	-	-

END

Project Info

• Repository: https://github.com/utags/userscript-api-benchmark
• Issues: https://github.com/utags/userscript-api-benchmark/issues
• License: MIT

Changelog

0.1.5

• Add addStyle and addElement test cases.

0.1.1

• Initial release.
• Support for GM.* (Promise) and GM_* (Callback/Sync) APIs.
• Comprehensive test coverage including storage, values, tabs, and window operations.