MSEdge

var isAudioContextSupported = function () {
    // This feature is still prefixed in Safari
    window.AudioContext = window.AudioContext || window.webkitAudioContext;
    if(window.AudioContext){
        return true;
    }
    else {
        return false;
    }
};

MSEdge

interface AesGcmEncryptResult {
    readonly attribute ArrayBuffer ciphertext;
    readonly attribute ArrayBuffer tag;

};

interface BookmarkCollection {
    readonly attribute long length;

    any item(unsigned long index);