The 90's. Microsoft and Netscape are throwing features at their browsers seeing what will stick.
Broken at birth (10 days!). Furthermore, Microsoft implemented bastardised version after bastardised version ('embrace, extend and exterminate') until it became virtually impossible to develop anything non-trivial that ran on more than one browser.
Communicate Communicate Communicate
Why is it important for financial analysts to write code that can run anywhere?
Firstly, at least half your job is the communication of your analysis and there's no better way to tell your story than through the browser.
Secondly, letting the client do all the computationally heavy lifting is the ultimate in massively distributed computing.
One of the most annoying is that by default variables are global. For example, passing a variable into a function and changing it within the function also changes it everywhere else!
Plus it's ugly. It looks like C. Too many curly braces.
It's hard to believe that a language created in ten days has conquered the world. If you are new to programming, it was built for you. Otherwise it will annoy the hell out of you.
Perhaps it's harder to understand how such a flawed language has such an iron grip on the developer community.
However, that's besides the point.
It excels at communicating ideas.