Question

I currently have the regex in a javascript file as:

function (value) {
    regex = new RegExp("[\<|\>|\"|\'|\%|\;|\(|\)|\&|\_|\.]", "i");
    return !regex.test(value);
}

Rather than specifying what characters are not allowed, how can I state what characters are allowed? The characters I want are a-z A-Z 0-9 (and also the actual character “-” but not at the start or end, only inbetween). Thanks in advanced.

Answer 1

regex = new RegExp("^[a-zA-Z0-9]+(?:-[a-zA-Z0-9]+)*$");

Again the classical “normal* (special normal*)*” pattern 😉

The function body becomes:

function (value) {
    regex = new RegExp("^[a-zA-Z0-9]+(?:-[a-zA-Z0-9]+)*$");
    return regex.test(value) && value.length >= 6;
}

edit: made grouping non capturing since no capture is done here