Regular Expression for Password Strength Validation

Question

I have written a regular expression which could potentially be used for password strength validation:

^(?:([A-Z])*([a-z])*(\\d)*(\\W)*){8,12}$

Answer 1

Here was my final solution based on sp00m's answer:

function testPassword(pwString) {
    var strength = 0;

    strength += /[A-Z]+/.test(pwString) ? 1 : 0;
    strength += /[a-z]+/.test(pwString) ? 1 : 0;
    strength += /[0-9]+/.test(pwString) ? 1 : 0;
    strength += /[\W]+/.test(pwString) ? 1 : 0;

    switch(strength) {
        case 3:
            // its's medium!
            break;
        case 4:
            // it's strong!
            break;
        default:
            // it's weak!
            break;
    }
}

I've added this purely for reference, however have accepted sp00m's answer since it was their answer that let me to this solution.