Just wanting to know. please help
In a word: no. 
Longer answer: I’m not a Unity user. I’ve never built anything with Unity. But I believe Unity’s implementation of JavaScript supports a bunch of stuff that ‘true’ JavaScript doesn’t. Things like operator overloading, co-routines (and the yield keyword) and so on. Personally, I think Unity have muddied the waters by calling their implementation JavaScript.
PlayCanvas, on the other hand, is an environment for programming in pure ‘true’ JavaScript. The code you write is what is directly executed by the browser. Indeed, you can use the browser’s dev tools to debug and profile the code you write. This is not something that happens with Unity since the code you write is cross-compiled to JavaScript via C++ and LLVM using Emscripten. (Yuck)
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