isIpAddress javascript web frontend

 function isIpAddress(str)
    {        
        thePat = /^(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])(\.(\d{1,2}|1\d\d|2[0-4]\d|25[0-5])){3}$/;
        if(thePat.test(str)){
            return true;
        }else{
            return false;
        }
    }