In the JavaScript console, type the following and hit enter.
alert("Hello world!");
That's great, but let's say you want to get some information from the person visiting your page.
prompt("What is your name?");
If you'd like, you can provide a default response.
prompt("Who is the best teacher ever?","Mr. Kinney");
Let's imagine for a moment that you only want a yes or no answer. Try this out:
confirm("Do you like jelly beans?");
Hitting "Okay" returns true and "Cancel" returns false.
The preferred way to debugging is to quietly log to the console itself. Give this a shot:
console.log("I am a banana.");
As you dive deeper into JavaScript, you'll be using this one more than the rest to figure out what's going on in your app.
Okay, this one is fun. Go to any page and toss this little snippet into the console.
document.body.contentEditable = 'true';
Now, go click on any text on the page and start typing. The entire page is now editable. You can type in anything you want.