使用JavaScript中的正则表达式精确匹配字符串

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.

Also as test() function evaluates the matches in the string and not the whole string https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp/test

Can someone please help. Thanks in advance

Answer 1

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 (ie 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 AZ .

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