Enissay

// Go to a steam group you're a member in, then click invite friends (big blue button on top left of the page)
// Then try to execute this code
// Later i'm going to check only a part of the disponible checkboxes
var i = 0;

$('input.friendCheckbox').each(function() {   //=> Uncaught TypeError: Cannot read property 'each' of null
    console.log(++i);
});