Why is this regular expression accepting special characters and numbers?

Question

I've created a simple regular expression for email. It is: /[a-z]+@{1}[a-z]{2,}/ Now the problem is that it's accepting an email like something;;99@asd when tested. But it shouldn't allow ;;99 ? I want letters only.

Secondly, please tell me about beginning (^) and end ($) symbols used in regular expression. I read about them on codeacademy but couldn't understand their purpose. Do they have something to do with my original problem?

EDIT: Here's the whole jQuery:

<script type="text/javascript">
    $(document).ready(function(){
        var $pat1=/[a-zA-Z0-9]{5}/;
        var $pat2=/[a-z]+@{1}[a-z]{2,}/;
        $(".savebutton").click(function(){
            var $name=$("input[name='pname']").val();
            var $email=$("input[name='pmail']").val();
            var $pswd=$("input[name='pswd']").val();
            if(($name!="" && $email!="") && $pswd!=""){
                if($pat1.test($name)&&$pat2.test($email)){
                    //ACTIONS               
                           }
                    }
        })
    })
</script>

The regex does not match the string you supplied. See https://regex101.com/r/yS6vX1/1. Are you sure you provided the same input you used in your code? — Wiktor Stribiżew, Jul 18 '16 at 08:48
As mentioned that regex doesn't match the email you provided. Please show how your consuming the regex — Liam, Jul 18 '16 at 08:51

score 2 · Accepted Answer · answered Jul 18 '16 at 08:51

2

Try this regex

/^[a-z]+@{1}[a-z]{2,}$/g

Your string must start with a-z (^) and end in a-z($)

^ and $ are for beginning and end

answered Jul 18 '16 at 08:51

Piyush.kapoor

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Thank you. Please read the EDIT in my question. – Jul 18 '16 at 08:53
Will it solve my problem? – Jul 18 '16 at 08:53
1

Yes it would just insert ^ and $ – Piyush.kapoor Jul 18 '16 at 08:55
1

Well it does. Can you tell why did it allow numbers and special chars when ^ and $ weren't used? – Jul 18 '16 at 08:55
I'm wondering how this could match a valid mail address, e.g. [`nobody@example.com`](https://regex101.com/r/kY1fX7/1) – Sebastian Proske Jul 18 '16 at 08:57
because it would match any contiguous string then for eg 999asas@asas , then it would match asas@asas – Piyush.kapoor Jul 18 '16 at 08:57
1

you need add .com or some other domain (regex) to be complete email regex – Piyush.kapoor Jul 18 '16 at 08:58
I'm just learning. Thanks for the help :) – Jul 18 '16 at 08:59
@SebastianProske keep wondering. – Jul 18 '16 at 09:00

score 0 · Answer 2 · answered Jul 18 '16 at 08:59

Your Regular Expression looks fine. I tested it on few test cases.

Symbol ^ Matches the beginning of the string, or the beginning of a line if the multiline flag (m) is enabled. This matches a position, not a character.
Symbol $ Matches the end of the string, or the end of a line if the multiline flag (m) is enabled. This matches a position, not a character.

For example, if you have to match pattern of exactly length 3, Then you can use ^ and $ to denote beginning and end of the pattern.

score 0 · Answer 3 · answered Jul 18 '16 at 09:28

An example of email regex is like this

 /^[+a-zA-Z0-9._-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}$/m

for your question,

Please tell me about beginning (^) and end ($) symbols used in regular expression...

In my example regex above, both symbols are best used if your using the multiline (m) modifier in you regex. (^) is used to identify the beginning of the line and ($) is used to identify the end of the line. It does affect your original problem but I would suggest you use this symbols in your regular expression.

Hope me help well.

Why is this regular expression accepting special characters and numbers?

3 Answers3