Exact match a string using Regular Expression in JavaScript

Question

I want to validate a string in JavaScript to allow alphanumerics, "(", ")" , and spaces. So test strings are:

s1 = "This $h00l*&^ not w0rk342*_(&, <and> always fail" 
s2 = "This should work (ABC1234)"

my code:

var regX = new RegExp(/A-Za-z0-9\\(\\)\\x20+/);
if(!regX.test(s1)){
    alert("InValid value.");
}

But it fails for both the strings.

Can someone please help. Thanks in advance

As written, your RE will just match strings containing "A-Za-z0-9() +" — bmm6o
– bmm6o, Commented Feb 6, 2014 at 17:21

nhahtdh · Accepted Answer · 2014-02-06 17:12:31Z

3

You should use this regex:

/^[A-Za-z0-9() ]*$/

Replace * with + if you don't want to allow empty string.

^ and $ test for beginning and the end of the string respectively.

* means repeat 0 or more times. + means repeat once or more.

To specify a character class (i.e. a set of character), you need to place the characters inside [].

To further shorten the regex:

/^[a-z\d() ]*$/i

i flag will make the regex matches case-insensitively, which remove the needs to specify A-Z.

\d is the shorthand character class for digits 0-9. Shorthand character class can also be included inside character class.

answered Feb 6, 2014 at 17:02

nhahtdh

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1 Comment

You could shorten it by using the i flag and removing the A-Z option, as well.