Why do yo use JavaScript-Libraries like jQuery?

jQuery was released in January 2006. At this time, IE6 was the major browser at the market, so everything concerning to JavaScript was a bit messed-up with Microsoft specific stuff, Firefox market share was growing, the need for animations combined with CSS 2 came up etc. pp.

Today, we have our browsers in a who-is-most-standard-compliant-competition and a lot of nice new APIs with most of the basic ones even supported by IE 8, so most of them have higher backwards-compatibility than jQuery 2.x, which officially only supports IE >9.x.

So I asked me: For which reason are most of the web developers using jQuery? I mean: Selecting DOM elements isn't an argument, Element.querySelector should be faster. AJAX complexibility isn't an argument, ActiveXObject is dead since IE 7. Animations aren't an argument, CSS 3 is grown-up. Since ECMAScript 5, there's Array.prototype.forEach. Events can be easily handled by CustomEvent.

If you're interested in these native APIs called WebAPI, just take a visit to MDN: https://developer.mozilla.org/en-US/docs/Web/API/Element.querySelector https://developer.mozilla.org/en-US/docs/Web/API/element https://developer.mozilla.org/en-US/docs/Web/API/Node https://developer.mozilla.org/en-US/docs/Web/API (Everything at a glance)