Javascript regular expression password validation having special characters

Solution 1:

Use positive lookahead assertions:

var regularExpression = /^(?=.*[0-9])(?=.*[!@#$%^&*])[a-zA-Z0-9!@#$%^&*]{6,16}$/;

Without it, your current regex only matches that you have 6 to 16 valid characters, it doesn't validate that it has at least a number, and at least a special character. That's what the lookahead above is for.

• (?=.*[0-9]) - Assert a string has at least one number;
• (?=.*[!@#$%^&*]) - Assert a string has at least one special character.

Solution 2:

function validatePassword() {
    var p = document.getElementById('newPassword').value,
        errors = [];
    if (p.length < 8) {
        errors.push("Your password must be at least 8 characters"); 
    }
    if (p.search(/[a-z]/i) < 0) {
        errors.push("Your password must contain at least one letter.");
    }
    if (p.search(/[0-9]/) < 0) {
        errors.push("Your password must contain at least one digit."); 
    }
    if (errors.length > 0) {
        alert(errors.join("\n"));
        return false;
    }
    return true;
}

There is a certain issue in below answer as it is not checking whole string due to absence of [ ] while checking the characters and numerals, this is correct version