Browser versions that support web workers?

Question

What are the earliest versions of Internet Explorer, Firefox, Chrome, Safari and Opera that define window.Worker?

W3Schools states

Internet Explorer 10, Firefox, Chrome, Safari and Opera support Web workers.

But it is a bit vague for me. It does not state which versions of all the latter browsers have web workers. Also, does this mean that Internet Explorer 9 does not have web workers?

Answer 1

From Can I Use...'s browser support for Web Workers:

The earliest versions which support Web Workers are:

• IE: 10
• Firefox: 3.5
• Chrome: 4
• Safari: 4
• Opera: 10.6

The Mozilla Developer Network's page on Web Workers also gives this information:

Feature         Chrome  Firefox (Gecko)  Internet Explorer  Opera  Safari (WebKit)
Basic support   4       Unknown (3.5)    10.0               10.6   4