1
00:00:00,190 --> 00:00:03,460
Our last field to validate
is an email address.

2
00:00:03,460 --> 00:00:06,740
The basic format for
an email address is simple.

3
00:00:06,740 --> 00:00:11,390
A string of characters followed by an @
sign, another string of characters,

4
00:00:11,390 --> 00:00:15,430
a dot, and then some top-level
domain like com or net.

5
00:00:15,430 --> 00:00:17,230
Why don't you pause the video here and

6
00:00:17,230 --> 00:00:20,660
try to complete the email
validation yourself first?

7
00:00:20,660 --> 00:00:22,000
Then, I'll show you my solution.

8
00:00:23,090 --> 00:00:24,310
So to start with,

9
00:00:24,310 --> 00:00:29,100
I'm going to add the things that
we know we're gonna have to have.

10
00:00:29,100 --> 00:00:34,140
So I'll put a regular expression,
and then I'll call test on it, and

11
00:00:34,140 --> 00:00:39,870
pass in email, and then I wanna
return this from our function.

12
00:00:41,350 --> 00:00:46,580
So emails normally have letters and
numbers before the @ symbol,

13
00:00:46,580 --> 00:00:51,510
as well as underscores, so we could match
repeated word characters at the beginning.

14
00:00:54,520 --> 00:00:58,330
But I've also seen them with dots and
pluses.

15
00:00:58,330 --> 00:01:03,100
Perhaps the safest way to match that
first segment is anything that is not

16
00:01:03,100 --> 00:01:04,676
an @ symbol.

17
00:01:07,407 --> 00:01:11,850
Notice I'm using a plus symbol for
the repetition instead of an asterisk.

18
00:01:11,850 --> 00:01:15,770
That's because there needs to be at
least one character before the @ sign.

19
00:01:15,770 --> 00:01:20,120
Any characters between the @ symbol and
the dot should be letters, but

20
00:01:20,120 --> 00:01:22,190
maybe numbers are allowed.

21
00:01:22,190 --> 00:01:25,970
To be safe, I'll just match anything
that's not an @ symbol or a dot.

22
00:01:31,450 --> 00:01:35,701
For the final stretch, I'm pretty
sure that only letters are allowed,

23
00:01:35,701 --> 00:01:37,730
so I'll just use a character set.

24
00:01:41,470 --> 00:01:45,290
Also, emails are case insensitive.

25
00:01:45,290 --> 00:01:49,090
I could add a capital A to Z inside
the character set to account for

26
00:01:49,090 --> 00:01:52,370
this, but I'll just set an i flag for
this example.

27
00:01:53,610 --> 00:01:56,430
Remember, this case insensitive flag

28
00:01:56,430 --> 00:02:00,470
makes the parser disregard case
when it looks for matches.

29
00:02:00,470 --> 00:02:03,830
Finally, let's add a carrot and
dollar sign as we've done before.

30
00:02:09,496 --> 00:02:14,690
I'll save and refresh the browser.

31
00:02:14,690 --> 00:02:23,220
And I'll type person@example.com,
and it works.

32
00:02:23,220 --> 00:02:26,360
This regular expression
will match most emails.

33
00:02:26,360 --> 00:02:30,950
Developers have some disagreement
around how to validate emails, though.

34
00:02:30,950 --> 00:02:34,370
Some say there are so
many validations that the only way to

35
00:02:34,370 --> 00:02:38,790
really know if you have a valid
email address is to send mail to it.

36
00:02:38,790 --> 00:02:43,110
So a production app might have some
minimal validation that uses an expression

37
00:02:43,110 --> 00:02:44,420
like this one.

38
00:02:44,420 --> 00:02:50,530
Then, it might send a verification
email to ensure the address' validity.

39
00:02:50,530 --> 00:02:51,980
Other developers disagree,

40
00:02:51,980 --> 00:02:55,710
believing that the best way to
validate is in the browser.

41
00:02:55,710 --> 00:02:58,595
Here's a site that aims to account for

42
00:02:58,595 --> 00:03:04,557
every possible email address with Regex
that also excludes all invalid ones.

43
00:03:04,557 --> 00:03:08,385
There's a lot of good information here
that I'll let you read through on

44
00:03:08,385 --> 00:03:08,960
your own.

45
00:03:08,960 --> 00:03:15,610
HTML also supports basic validation
of a specific email input type.

46
00:03:15,610 --> 00:03:18,390
See the teacher's notes for
more information.

47
00:03:18,390 --> 00:03:22,970
So far, we've been testing strings
to see if they match expressions.

48
00:03:22,970 --> 00:03:25,780
Next, let's look at how
we can go further and

49
00:03:25,780 --> 00:03:29,450
replace parts of strings
using regular expressions.

50
00:03:29,450 --> 00:03:30,010
See you there.