[throw1111221]

Python went through a massive effort to add support for type annotations due to user demand.

Similarly, there's great demand for a typed layer on top of Javascript:

- Macromedia: (2000) ActionScript

- Google: (2006) GWT [Compiling Java to JS], and (2011) Dart

- Microsoft: (2012) Typescript

[teddyh]

You’re talking about static typing, the opposite of which is dynamic typing. User hamstergene is talking about weak vs. strong typing, which is another thing entirely. Python has always been strongly typed, while JavaScript is weakly typed. Many early languages with dynamic types also experimented with weak typing, but this is now, as hamstergene points out, considered a bad idea, and virtually all modern languages, including Python, are strongly typed.