How to remove everything but letters, numbers, space, exclamation and question mark from string?

You can use regex

myString.replace(/[^\w\s!?]/g,'');

This will replace everything but a word character, space, exclamation mark, or question.

Character Class: \w stands for "word character", usually [A-Za-z0-9_]. Notice the inclusion of the underscore and digits.

\s stands for "whitespace character". It includes [ \t\r\n].

If you don't want the underscore, you can use just [A-Za-z0-9].

myString.replace(/[^A-Za-z0-9\s!?]/g,'');

For unicode characters, you can add something like \u0000-\u0080 to the expression. That will exclude all characters within that unicode range. You'll have to specify the range for the characters you don't want removed. You can see all the codes on Unicode Map. Just add in the characters you want kept or a range of characters.

For example:

myString.replace(/[^A-Za-z0-9\s!?\u0000-\u0080\u0082]/g,'');

This will allow all the previously mentioned characters, the range from \u0000-\u0080 and \u0082. It will remove \u0081.

Both answers posted so far left out the question mark. I would comment on them, but don't have enough rep yet.

David is correct, sachleen's regex will leave underscores behind. rcdmk's regex, modified as follows, will do the trick, although if you care about international characters things might get a lot more complicated.

var result = text.replace(/[^a-zA-Z0-9\s!?]+/g, '');

This will leave behind new lines and tabs as well as spaces. If you want to get rid of new lines and tabs as well, change it to:

var result = text.replace(/[^a-zA-Z0-9 !?]+/g, '');

text = "A(B){C};:a.b*!c??!1<>2@#3"result = text.replace(/[^a-zA-Z0-9]/g, '')

Should return ABCabc123

First, we define text as A B C a b c 1 2 3 but with random characters set the result as:

text.replace(...) where the parameters are:

/.../g, /.../: ^ means to reverse; not to remove the letters which are:

a-z(lowercase letters), A-Z(UPPERCASE letters) and 0-9(digits)

g means global, to remove all matches not just the first match

The second parameter is the replacement character, we set it to an empty string so that it just keeps the specified string. if is specified, it will return this: "A B C a b c 1 2 3"