gistfile1.js

function password_strength(password, username) {
    var p = password
        , u = username
        ;
    
    if(
        /^[a-z]*$/.test(p)
        || /^[A-Z]*$/.test(p)
        || /^[0-9]*$/.test(p)
    ) {
        if(
            (p.length < 8)
            || p == u
        ) {
            return 'weak';
        }
        
        if(p.indexOf(u) != 1) {
            return 'fair';
        }
    }
    
    if(
        !/^[a-zA-Z0-9]*$/.test(p)
    ) {
        return 'strong';
    }

    if(
        (/[a-z]*/.test(p) && /[A-Z]*/.test(p))
        || /^[a-zA-Z]*$/.test(p) 
        || (!/^[a-zA-Z]*$/.test(p) && !/^[0-9]*$/.test(p))
    ) {
        return 'medium';
    }
    
}