function vf() {

valid = true;
var f = document.forms[0]


        if (f.user.value == "" ){
        var xx = document.getElementById('errorlogin')        

            xx.style.display='block';
            xx.innerHTML = 'Wpisz login.';  
            valid = false;
        }else {xx.style.display='none';}


        if (f.pass.value == "" ){
        var xxx = document.getElementById('errorpass')        

            xxx.style.display='block';
            xxx.innerHTML = 'Wpisz hasło.';  
            valid = false;
        }else {xxx.style.display='none';}

return valid;
}

onsubmit="return vf();"

function vf() {

valid = true;
var f = document.forms[0]

var xx = document.getElementById('errorlogin');
        if (f.user.value == "" ){    

            xx.style.display='block';
            xx.innerHTML = 'Wpisz login.';  
            valid = false;
        }else {xx.style.display='none';}

var xxx = document.getElementById('errorpass');
        if (f.pass.value == "" ){        

            xxx.style.display='block';
            xxx.innerHTML = 'Wpisz hasło.';  
            valid = false;
        }else {xxx.style.display='none';}

return valid;
}

mint.fx.Fade("errorlogin", 100, 20, 500);

function FadeIn() {
    mint.fx.Fade("errorlogin", 100, 20, 500);
}