The pros are obviously in any other case than the one your using here.
Jeroen Rombouts

Respectively disagree. JavaScript’s loose typing is the source of many WATs and WTFs that make JavaScript the butt of many jokes, for example, see Kyle Simpson’s talk.

A language like Smalltalk is just as powerful and just as flexible as JavaScript, and much easier to use. It doesn’t have any of JavaScript’s nonsense. It’s dynamically typed and strongly typed. Any sane person would choose Smalltalk over JavaScript. (I use Amber Smalltalk for web development.)

However, JavaScript is the only language native to the web browser, so you have no choice with respect to web development. That doesn’t make it a good language, only a necessary one.