Everything that we've put in our webpages so far
has been either content displayed by the browser,
or tags to tell the browser how to display it.
Sometimes though, we just want to put information in our webpages
for other humans to read, and for the browser to ignore.
To do that, we write an opening angle-bracket,
an exclamation mark, two dashes,
and some text inside here,
and then two dashes and a closing angle-bracket.
We call this a comment.
And it's something that we do in all sorts of programming languages,
because we often want to do things that are just for humans.
That's the thing about programs:
they're not just for computers to look at,
they're also for other humans to look at.
Because we often work together on things and learn from each other.
Okay, what do we use comments for,
besides just saying "hello" to our fellow humans?
Well, we might use them for letting people know
where content came from, in case they want to update it.
I'll say, "This paragraph is based on the Wikipedia article,"
and I should probably give a link to that, too, but...
And, "This paragraph is based on Pamela's personal opinion,"
a very well trusted source.
Then maybe we'd even, say, give a link inside the comments,
and say, "These lyrics were from here."
And that helps people know how I got the content of this page.
Do you notice something about these comments?
They are all green.
That's because we're using a code editor with syntax highlighting,
and it uses colors to help us see what's what,
and comments are pretty much always colored green, by convention.
We could also use comments to "comment out" parts of our HTML.
Like if we want to experiment with taking something away from our webpage.
We just surround it with a comment.
♪ (humming) ♪
Now, the browser no longer sees that HTML,
because browsers ignore everything in comments,
and that part is gone from the page.
If I decide that I actually liked it, I can comment it back in
by removing those comments on both sides...
and now it's back!
Remember, comments are for humans.
At least, the kind of humans that like to look at webpage code.
Which is pretty much all of us now, right?