Complete Chrome console stretch task

Author: BrianY315

Sprint-2/4-stretch-explore/chrome.md

@@ -8,8 +8,12 @@ Let's try an example.
 In the Chrome console, invoke the function `alert` with one argument, the string `"Hello world!"`;
 
 What effect does calling the `alert` function have?
+It shows a pop-up dialog box with the message "Hello world!" and pauses the browser until the user closes it.
 
 Now try invoking the function `prompt` with a string input of `"What is your name?"` - store the return value of your call to `prompt` in an variable called `myName`.
 
 What effect does calling the `prompt` function have?
+It displays a dialog box asking the user for input.
+
 What is the return value of `prompt`?
+The return value is the text entered by the user as a string. If the user cancels the prompt, it returns `null`.