Make a summary of this including tools and what they are used for: "In this video we will review Hypertext Markup Language or HTML for Webscraping. Lots of useful data is available on web pages, such as real estate prices and solutions to coding questions. The website Wikipedia is a repository of the world's information. If you have an understanding of HTML, you can use Python to extract this information. In this video, you will: review the HTML of a basic web page; understand the Composition of an HTML Tag; understand HTML Trees; and understand HTML Tables. Let’s say you were asked to find the name and salary of players in a National Basketball League from the following web page. The web page is comprised of HTML. It consists of text surrounded by a series of blue text elements enclosed in angle brackets called tags. The tags tells the browser how to display the content. The data we require is in this text. The first portion contains the "DOCTYPE html” which declares this document is an HTML document.

<html> element is the root element of an HTML page,  and <head> element contains meta information about the HTML page. Next, we have the body, this is what's displayed on the web page. This is usually the data we are interested in, we see the elements with an “h3”, this means type 3 heading, makes the text larger and bold. These tags have the names of the players, notice the data is enclosed in the elements. It starts with a h3 in brackets and ends in a slash h3 in brackets. There is also a different tag “p”, this means paragraph, each p tag contains a player's salary. Let’s take a closer look at the composition of an HTML tag. Here is an example of an HTML Anchor tag. It will display IBM and when you click it, it will send you to IBM.com. We have the tag name, in this case “a”. This tag defines a hyperlink, which is used to link from one page to another. It’s helpful to think of each tag name as a class in Python and each individual tag as an instance. We have the opening or start tag and we have the end tag. This has the tag name preceded by a slash. These tags contain the content, in this case what’s displayed on the web page. We have the attribute, this is composed of the Attribute Name and Attribute Value. In this case it the url to the destination web page. Real web pages are more complex, depending on your browser you can select the HTML element, then click Inspect. The result will give you the ability to inspect the HTML. There is also other types of content such as CSS and JavaScript that we will not go over in this course. The actual element is shown here. Each HTML document can actually be referred to as a document tree. Let's go over a simple example. Tags may contain strings and other tags. These elements are the tag’s children. We can represent this as a family tree. Each nested tag is a level in the tree. The tag HTML tag contains the head and body tag. The Head and body tag are the descendants of the html tag. In particular they are the children of the HTML tag. HTML tag is their parent. The head and body tag are siblings as they are on the same level. Title tag is the child of the head tag and its parent is the head tag. The title tag is a descendant of the HTML tag but not its child. The heading and paragraph tags are the children of the body tag; and as they are all children of the body tag they are siblings of each other. The bold tag is a child of the heading tag, the content of the tag is also part of the tree but this can get unwieldy to draw.

Next, let’s review HTML tables. To define an HTML table we have the table tag. Each table row is defined with a  <tr>  tag, you can also use a table header tag for the first row. The table row cell contains a set of <td> tags, each defines a table cell. For the first row first cell we have; for the first row second cell we have; and so on. For the second row we have; and for the second row first cell we have; for the second row second cell we have; and so on. We now have some basic knowledge of HTML. Now let's try and extract some data from a web page."