Get all non standard variables defined in the global context

get-global-vars.js

// make sure it doesn't count my own properties
(function () {
    var results, currentWindow,
    // create an iframe and append to body to load a clean window object
    iframe = document.createElement('iframe');
    iframe.style.display = 'none';
    document.body.appendChild(iframe);
    // get the current list of properties on window
    currentWindow = Object.getOwnPropertyNames(window);
    // filter the list against the properties that exist in the clean window
    results = currentWindow.filter(function(prop) {
        return !iframe.contentWindow.hasOwnProperty(prop);
    });

    let result = {};
    results.forEach(r => {
        result[r] = window[r];
    })

    console.log(result)

    document.body.removeChild(iframe);
}());