Как бы уязвимость
script
var login = Object();
function login_status(a, b) {
div = document.createElement('div');
if (b == 1){
div.innerHTML = a + ': logged in';
div.style.color = 'red';
} else {
div.innerHTML = a + ': not logged in';
div.style.color = 'green';
}
document.body.appendChild(div);
};
function img(a, b) {
var i = new Image();
i.onload = function () {
login_status(b, 1);
i = i.onload = i.onerror = undefined
};
i.onerror = function () {
login_status(b, 0);
i = i.onload = i.onerror = undefined
};
i.src = a
};