How to generate random number excluding a previously generated number

Hi,

I am new to web development so I am still kind of unsure to how everything works so sorry if it is something obvious.

To create the scenario, I need to create a music player using html5, javascript and css. I very much got stuck on how to shuffle the songs that I have so that a random order is created and the previously played songs dont play after.

I have used a checkbox to create the shuffle 'button' which looks like this in html:

        <input type="checkbox" value="None" id="random_song" onclick="shuffleSong()" name="check" />
        <label class="random" for="random_song"></label>

and then I have created the following code in javascript to shuffle:

function shuffleSong() {
    const song = document.querySelector('#song')
    var shuffle = document.getElementById('random_song');
    var y = 0;
    song.addEventListener('ended', function () {
        if (shuffle.checked) {
            var x = Math.floor((Math.random() * 7));
            alert(x); // this is just for testing so I know which array element it will play

            song.src = songs[x];
            thumbnail.src = thumbnails[x];
            background.src = thumbnails[x];
            songArtist.innerHTML = songArtists[x];
            songTitle.innerHTML = songTitles[x];
            playing = true;
            playPause();;
        } else { //this works perfectly
            y++;
            if (y > 6) {
                y = 0;
            };
            song.src = songs[y];
            thumbnail.src = thumbnails[y];
            background.src = thumbnails[y];

            songArtist.innerHTML = songArtists[y];
            songTitle.innerHTML = songTitles[y];

            playing = true;
            playPause();
        }
    });
}

The following are arrays: song, thumbnail, background, songArtist and songTitle which of course contain all the relevant information for the songs that will be played.
The playPause() is a function to just automatically start playing the song as well if the play button is on.

Is there anyone who could tell me what I need to add to the code to eliminate the previously created random number?

Thank you so much in advance :)