Javascript Christmas Cards

<!DOCTYPE html>
<html>
<head>
<script>

function domything () {
    var x = document.getElementById("xmas");
    // console.log("x is", x, x.currentTime, x.duration);
    x.currentTime = x.duration / 2;
}

function start () {
    var x = document.getElementById("xmas");
    x.addEventListener("durationchange", domything, false);
    x.addEventListener("play", function () {
        body =document.getElementsByTagName("body")[0];
        body.style.background = "black";
    }, false);
    x.addEventListener("pause", function () {
        body =document.getElementsByTagName("body")[0];
        body.style.background = "";
    }, false);
    x.addEventListener("timeupdate", function () {
        if (x.currentTime > 56) {
            x.currentTime = x.duration / 2;
        }
    }, false);


}

document.addEventListener("DOMContentLoaded", start, false);

</script>
</head>

<body>
<center>
<video id="xmas" controls src="Prozim-Christmas863.ogv">No video support!</video>
</center>
</body>

</html>
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