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How can I quickly validate if a string is alphabetic only, e.g
var str = "!";
alert(isLetter(str)); // false
var str = "a";
alert(isLetter(str)); // true
Edit : I would like to add parenthesis i.e () to an exception, so
var str = "(";
or
var str = ")";
should also return true.
753
Use the test() method to check if a string contains only letters, e.g. /^[a-zA-Z]+$/. test(str) . The test method will return true if the string contains only letters and false otherwise.
You will use the given regular expression to validate user input to allow only alphanumeric characters. Alphanumeric characters are all the alphabets and numbers, i.e., letters A–Z, a–z, and digits 0–9.
To check if a string contains any letters, use the test() method with the following regular expression /[a-zA-Z]/ . The test method will return true if the string contains at least one letter and false otherwise.
Regular expression to require at least one letter, or paren, and only allow letters and paren:
function isAlphaOrParen(str) {
return /^[a-zA-Z()]+$/.test(str);
}
Modify the regexp as needed:
/^[a-zA-Z()]*$/ - also returns true for an empty string/^[a-zA-Z()]$/ - only returns true for single characters./^[a-zA-Z() ]+$/ - also allows spaces
165
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