Merge pull request #943 from honzajavorek/honzajavorek/mdn

refactor: link to MDN as a canonical resource

Author: honzajavorek

sources/academy/tutorials/apify_scrapers/getting_started.md

@@ -152,7 +152,7 @@ In the structures, only the `OWNER` and `NAME` change. We can leverage this in a
 
 #### Making a pseudo URL
 
-**Pseudo URL**s are really just URLs with some variable parts in them. Those variable parts are represented by [regular expressions](https://regexone.com/) enclosed in brackets `[]`.
+**Pseudo URL**s are really just URLs with some variable parts in them. Those variable parts are represented by [regular expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) enclosed in brackets `[]`.
 
 Working with our actor details example, we could produce a **Pseudo URL** like this:
 

sources/academy/webscraping/puppeteer_playwright/common_use_cases/paginating_through_results.md

@@ -101,7 +101,7 @@ await browser.close();
 </TabItem>
 </Tabs>
 
-> Learn more about the `:nth-last-child` pseudo-class [on W3Schools](https://www.w3schools.com/cssref/sel_nth-last-child.asp). It works similar to `:nth-child`, but starts from the bottom of the parent element's children instead of from the top.
+> [Learn more](https://developer.mozilla.org/en-US/docs/Web/CSS/:nth-last-child) about the `:nth-last-child` pseudo-class. It works similar to `:nth-child`, but starts from the bottom of the parent element's children instead of from the top.
 
 When we run this code, here's what we see:
 

sources/academy/webscraping/web_scraping_for_beginners/crawling/filtering_links.md

@@ -105,7 +105,7 @@ If you try this in Node.js instead of DevTools, you will not get the full URLs,
 
 Another common way to filter links (or any text, really) is by matching patterns with regular expressions.
 
-> [Learn more about regular expressions](https://javascript.info/regexp-introduction)
+> [Learn more about regular expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions)
 
 When we inspect the product URLs, we'll find that they all look like the following:
 

sources/academy/webscraping/web_scraping_for_beginners/data_extraction/browser_devtools.md

@@ -67,7 +67,7 @@ By changing HTML elements from the Console, you can change what's displayed on t
 
 ![Chrome DevTools JavaScript command execution](./images/browser-devtools-console-commands.png)
 
-> You can interact with the page in many more ways using the Console. If you want to dive deeper we recommend this [tutorial on documents](https://javascript.info/document). A web page in a browser is called a document.
+> In JavaScript, the web page is called `document`. From the Console you can interact with it in many ways. Go through [document basics](https://developer.mozilla.org/en-US/docs/Web/API/Document_object_model/Using_the_Document_Object_Model) to learn more.
 
 ## Next up {#next}
 

sources/academy/webscraping/web_scraping_for_beginners/data_extraction/index.md

@@ -18,19 +18,19 @@ Every web scraping project starts with some detective work. To a human, it's com
 
 For the browser to be able to show you the web page with all its text and images, the data needs to be present somewhere. This data source is called HTML (HyperText Markup Language) and it gets downloaded to your computer whenever you open a website. If you want to extract data from a website, you need to show your computer where to find it in the HTML.
 
-> To learn about HTML, we recommend browsing the [MDN tutorials on HTML](https://developer.mozilla.org/en-US/docs/Web/HTML).
+> To learn more about markup, we recommend the [resources about HTML](https://developer.mozilla.org/en-US/docs/Learn/HTML) provided by MDN, the official documentation of the web.
 
 ## CSS {#css}
 
-CSS (Cascading Style Sheets) is a markup language that is used to give websites their style. It controls shapes, colors, positioning and even animations. The style is then added to the page's HTML and together, they define the page's content and structure. In web scraping, we can leverage CSS to find the data we want using CSS selectors.
+CSS (Cascading Style Sheets) is a language that is used to give websites their style. It controls shapes, colors, positioning and even animations. The style is then added to the page's HTML and together, they define the page's content and structure. In web scraping, we can leverage CSS to find the data we want using CSS selectors.
 
-> Find more information on CSS and CSS selectors in the [MDN tutorials on CSS](https://developer.mozilla.org/en-US/docs/Web/CSS).
+> To learn more about styles and selectors, we recommend the [resources about CSS](https://developer.mozilla.org/en-US/docs/Learn/CSS) provided by MDN, the official documentation of the web.
 
 ## JavaScript {#javascript}
 
 HTML and CSS give websites their structure and style, but they are static. To be able to meaningfully interact with a website, you need to throw JavaScript into the mix. It is the language of the web, and you don't need to be a programmer to learn the basics. You don't even need any special software, because you can try it right now, in your browser.
 
-> If you want to dive deeper into JavaScript, check out [this great tutorial](https://javascript.info/).
+> To learn more about programming in browser, we recommend the [resources about JavaScript](https://developer.mozilla.org/en-US/docs/Learn/JavaScript) provided by MDN, the official documentation of the web.
 
 ## Next up {#next}
 

sources/academy/webscraping/web_scraping_for_beginners/data_extraction/node_js_scraper.md

@@ -32,7 +32,7 @@ console.log(html);
 
 Now run the script using the `node main.js` command from the previous lesson. After a brief moment, you should see the page's HTML printed to your terminal.
 
-> `gotScraping` is an `async` function and the `await` keyword is used to pause execution of the script until it returns the `response`. [Learn more about `async` and `await`](https://javascript.info/async-await)
+> `gotScraping` is an `async` function and the `await` keyword is used to pause execution of the script until it returns the `response`. If you're new to this, go through an [introduction to asynchronous JavaScript](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/Asynchronous).
 
 ## Parsing HTML {#parsing-html}
 

sources/academy/webscraping/web_scraping_for_beginners/data_extraction/using_devtools.md

@@ -83,18 +83,16 @@ The `product-item` class is simple, human-readable, and semantically connected w
 
 ## Extracting data from elements {#extraction-from-elements}
 
-Now that we found the element, we can start poking into it to extract data. First, let's save the element to a variable so that we can work with it repeatedly.
-
-Run the commands in the Console:
+Now that we found the element, we can start poking into it to extract data. First, let's save the element to a variable so that we can work with it repeatedly. Run these commands in the Console:
 
 ```js
 const products = document.querySelectorAll('.product-item');
 const subwoofer = products[2];
 ```
 
-> If you're wondering what an array is or what `products[2]` means, learn more in [this tutorial on JavaScript arrays](https://javascript.info/array).
+> If you're wondering what an array is or what `products[2]` means, read the [JavaScript arrays basics](https://developer.mozilla.org/en-US/docs/Learn/JavaScript/First_steps/Arrays).
 
-Now that we have the subwoofer saved into a variable, run another command in the Console to print its text:
+Now that we have the subwoofer saved in a variable, run another command in the Console to print its text:
 
 ```js
 subwoofer.textContent;
@@ -150,7 +148,7 @@ It worked, but the price was not alone in the result. We extracted it together w
 When it comes to data cleaning, there are two main approaches you can take. It's beneficial to understand both, as one approach may be feasible in a given situation while the other is not.
 
 1. Remove the elements that add noise to your data from the selection. Then extract the pre-cleaned data.
-2. Extract the data with noise. Use regular expressions or other text manipulation techniques to parse the data and keep only the parts we're interested in.
+2. Extract the data with noise. Use [regular expressions](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions) or other text manipulation techniques to parse the data and keep only the parts we're interested in.
 
 First, let's look at **removing the noise before extraction**. When you look closely at the element that contains the price, you'll see that it includes another `<span>` element with the text **Sale price**. This `<span>` is what adds noise to our data, and we have to get rid of it.
 

sources/academy/webscraping/web_scraping_for_beginners/index.md

@@ -41,7 +41,7 @@ This is what you'll learn in the **Web scraping for beginners** course:
 
 You don't need to be a developer or a software engineer to complete this course, but basic programming knowledge is recommended. Don't be afraid, though. We explain everything in great detail in the course and provide external references that can help you level up your web scraping and web development skills. If you're new to programming, pay very close attention to the instructions and examples. A seemingly insignificant thing like using `[]` instead of `()` can make a lot of difference.
 
-> If you don't already have basic programming knowledge and would like to be well-prepared for this course, we recommend taking a [JavaScript course](https://www.codecademy.com/learn/introduction-to-javascript) and learning about [CSS Selectors](https://www.w3schools.com/css/css_selectors.asp).
+> If you don't already have basic programming knowledge and would like to be well-prepared for this course, we recommend learning about [JavaScript basics](https://developer.mozilla.org/en-US/curriculum/core/javascript-fundamentals/) and [CSS Selectors](https://developer.mozilla.org/en-US/docs/Learn/CSS/Building_blocks/Selectors).
 
 As you progress to the more advanced courses, the coding will get more challenging, but will still be manageable to a person with an intermediate level of programming skills.