As far as I know, that's because Java was the world's first programming language at the time when Netscape and Brendan Eich developed JavaScript. The story of JavaScript is certainly one of the most chaotic. Very interesting story tho

Him: I spend 3months on this project Me: how many lines does it takes now? Him: I would say around one line of code

I meant for my personal projects. For the code that only I see, tabs are much better for navigation. But it's true that if there are several of us working on the project, the spaces are much better.