是的，你需要 $（）当你'重新使用jQuery。如果你想让jQuery帮助做DOM事情，请记住这一点。

Yes you only need $() when you're using jQuery. If you want jQuery's help to do DOM things just keep this in mind.

$(this)[0] === this

基本上每当你得到一组元素时，jQuery会把它变成 jQuery对象。如果你知道你只有一个结果，它就会出现在第一个元素中。

Basically every time you get a set of elements back jQuery turns it into a jQuery object. If you know you only have one result, it's going to be in the first element.

$("#myDiv")[0] === document.getElementById("myDiv");

依此类推......

And so on...