The "Before Era" mentioned in the article can probably be subdivided further - it casually mentions that back then, "the most common thing you would do was include jQuery, throw together some scripts for a few UI widgets, and call it a day". However that was only possible after jQuery was released in 2006. Before that were the real "dark ages" of JS development, with primitive libraries, even more primitive dev tools in the browser (Firebug was also only released in 2006, and Chrome was the first browser to have integrated dev tools in 2008) and stuff like "be careful with console.log in IE, because it will crash your script unless the console is actually visible".