Add alert and prompt function explanation

Author: carlosyabreu

Sprint-1/4-stretch-explore/chrome.md

@@ -16,3 +16,70 @@ Now try invoking the function `prompt` with a string input of `"What is your nam
 
 What effect does calling the `prompt` function have?
 What is the return value of `prompt`?
+
+1. The alert() function
+
+Code:
+
+alert("Hello world!");
+
+Effect:
+
+When you call alert("Hello world!") in the Chrome Console:
+
+A modal dialog box (popup window) appears on the screen.
+
+It displays the message:
+
+Hello world!
+
+The dialog has an “OK” button that you must click before continuing.
+
+Purpose:
+It’s used to display information to the user — a simple way to show messages or debugging output in the browser.
+
+Return value:
+
+alert() does not return any value — its return value is undefined.
+
+2. The prompt() function
+
+Code:
+
+let myName = prompt("What is your name?");
+
+Effect:
+
+When you call this:
+
+A popup dialog appears with:
+
+A message: "What is your name?"
+
+A text input box
+
+“OK” and “Cancel” buttons.
+
+The user can type something (e.g., Alice) and click “OK” or “Cancel”.
+
+Return value:
+
+If the user types something (e.g., "Alice") and clicks OK 
+prompt() returns the string "Alice".
+
+If the user clicks Cancel 
+prompt() returns null.
+
+So after running:
+
+let myName = prompt("What is your name?");
+
+You’ll have:
+
+myName === "Alice" (if entered “Alice”)
+
+myName === null (if Cancelled)
+
+Purpose:
+prompt() is used to get text input from the user through a browser dialog.
+