content improvements

1-js/11-async/01-callbacks/article.md

@@ -2,10 +2,12 @@
 
 # Introduction: callbacks
 
-```warn header="We use browser methods here"
-To demonstrate the use of callbacks, promises and other abstract concepts, we'll be using some browser methods; specifically, loading scripts and performing simple document manipulations.
+```warn header="We use browser methods in examples here"
+To demonstrate the use of callbacks, promises and other abstract concepts, we'll be using some browser methods: specifically, loading scripts and performing simple document manipulations.
 
-If you're not familiar with these methods, and their usage in the examples is confusing, or if you would just like to understand them better, you may want to read a few chapters from the [next part](/document) of the tutorial.
+If you're not familiar with these methods, and their usage in the examples is confusing, you may want to read a few chapters from the [next part](/document) of the tutorial.
+
+Although, we'll try to make things clear anyway. There won't be anything really complex browser-wise.
 ```
 
 Many actions in JavaScript are *asynchronous*. In other words, we initiate them now, but they finish later.
@@ -18,13 +20,15 @@ Take a look at the function `loadScript(src)`, that loads a script with the give
 
 ```js
 function loadScript(src) {
+  // creates a <script> tag and append it to the page
+  // this causes the script with given src to start loading and run when complete
   let script = document.createElement('script');
   script.src = src;
   document.head.append(script);
 }
 ```
 
-It appends to the document the new, dynamically created, tag `<script src="…">`. The browser loads and executes it.
+It appends to the document the new, dynamically created, tag `<script src="…">` with given `src`. The browser automatically starts loading it and executes when complete.
 
 We can use this function like this: