LEVEL 1

1) DOM (Document Object Model) is a tree-like structure created by browser so we can quickly find HTML elements using Javascript
2) JQuery is a concise and fast Javascript library that can be used to simplify event handling, HTML document traversing, Ajax interactions and animation for
speedy website develpment
3) First, download JQuery from jquery.com as a .js file. Then, write inside the body element of the html file <script src=""></script>, wehere inside the "" lies
the path of the jquery file
4)Javascript may execute before the DOM loads. So, we need to make sure the DOM will have finished loading when JS interacts with it.
Thats why we use jQuery(document).ready(function(){}); and put inside the {} the function we wish to call
5) JQuery("h1"); OR $("h1); , if we wish to select the h1 element

LEVEL 2

1) the descendant selector is li and it means "choose all the li elements that are inside the element with id: destinations"
2) the descendant selector selects all the elements that are inside of the first element, in any html block and level. The child selector selects all
the elements that are inside of the first element but are specificly its children, which means the elements that exist only 1 level below the first element
3) traversing the DOM
4) the ul element
5) the body element
6) a) all the li elements 1 level underneath the #destinations id
   b) all the li elements that underneath all the levels of #destinations id

LEVEL 3

1) it doesn't remove the <button> element
2) Event delegation is a way to attach a handler to an html element and whenever an event occurs, the handler executes a function
3) it removes a button, when we click on it
4) it removed a button, when we click on it, but only if the button belongs in a vacation class

LEVEL 4

1) It's a function that prevents an element from doing its default behaviour, which in our case is a link and we use it in order to prevent it from popping
up to the start of the page