jumpToSecondBeforeEnd.js

// Find a <video> tag by class, and set the currentTime equal to its duration less one second.

function jumpToSecondBeforeEnd() {
    var className = "myClass";
    var video = document.getElementsByClassName(className)[0];

    // Check if the video metadata is loaded and duration is available
    if (!isNaN(video.duration) && isFinite(video.duration)) {
        // Calculate the target time: duration minus 1 second
        var targetTime = video.duration - 1;

        // Ensure the target time is not before the beginning of the video
        if (targetTime >= 0) {
            video.currentTime = targetTime;
            // Optional: start playing immediately
            // video.play();
        } else {
            console.log("Video is less than 1 second long.");
        }
    } else {
        console.log("Video duration is not yet available. Try again after the video loads metadata.");
        // You can add an event listener here to run the function when metadata loads
        video.addEventListener('loadedmetadata', jumpToSecondBeforeEnd, { once: true });
    }
}