This complaint is outdated. The dev tools that come built in with browsers are pretty damn good these days. They provide a Javascript console and debugger, as w

This complaint is outdated. The dev tools that come built in with browsers are pretty damn good these days. They provide a Javascript console and debugger, as well as a DOM inspector and a request inspector. So it's actually really easy now to figure out what's going on with your JS code. There are unit test frameworks for JS now too. Bad JS is still bad, but it's much easier to write good JS now than it used to be.