For those that are new to Tcl, there's an alternate universe where Tcl is the browser language instead of Javascript:
"Interesting footnote: the founding of Netscape occurred at the same time I was deciding where to go in industry when I left Berkeley in 1994. Jim Clarke and Marc Andreessen approached me about the possibility of my joining Netscape as a founder, but I eventually decided against it (they hadn't yet decided to do Web stuff when I talked with them). This is one of the biggest "what if" moments of my career. If I had gone to Netscape, I think there's a good chance that Tcl would have become the browser language instead of JavaScript and the world would be a different place! However, in retrospect I'm not sure that Tcl would actually be a better language for the Web than JavaScript, so maybe the right thing happened."
Perhaps. I think one of the main reasons JS caught on is that it had no significant baggage and the designers could take it in any direction it needed to go. Every language used by more than a few people, no matter how good it is, has some baggage. As a result, in that alternate universe, the browser scripting language landscape might have been a lot more fragmented.
The work on the safe subset of Tcl for the web can be exploited today to run untrusted scripts in an easily managed sandbox. If you want you can strip away enough commands for the language to be non-Turing complete.
I'm pretty sure some fellow students came into our computer room before that, "look now there even is a TK plugin for Mosaic!". it was not in "look it's like gopher but with a mouse!" days, but not that much later.
however you of course had to _do_ something to use it, while JavaScript came out of the box (once it was there).
I doubt the world would have stuck with TCL if that had happened. JavaScript was good enough for people to put up with. TCL definitely isn't. More likely we would have ended up with TCL + something else, with TCL deprecated.
"Interesting footnote: the founding of Netscape occurred at the same time I was deciding where to go in industry when I left Berkeley in 1994. Jim Clarke and Marc Andreessen approached me about the possibility of my joining Netscape as a founder, but I eventually decided against it (they hadn't yet decided to do Web stuff when I talked with them). This is one of the biggest "what if" moments of my career. If I had gone to Netscape, I think there's a good chance that Tcl would have become the browser language instead of JavaScript and the world would be a different place! However, in retrospect I'm not sure that Tcl would actually be a better language for the Web than JavaScript, so maybe the right thing happened."
Source: https://pldb.io/blog/JohnOusterhout.html