JavaScript gallery with mouse hold loop

Question

You can try hooking mousehold in this way:

in mouseDown event function set an interval and immediately execute it; inside the interval make the prev/next action
in window.onmouseup event function clear the interval

Consider to remove inline event bindings..

HTML:

<a href="#" onMousedown="next(); return false;">Next</a>

<a href="#" onMousedown="previous(); return false;">Back</a>

<img id="gallery" src="http://placehold.it/350x150" style="height:420px;width:744px">

Code:

var imageGallery = [
    "http://placehold.it/350x150",
    "http://placehold.it/350x250",
    "http://placehold.it/350x350",
    "http://placehold.it/350x450"];

var imgCount = 0;
var totalImgs = imageGallery.length - 1;
var timer;

function next() {
    timer = setInterval(function fn() {
        imgCount++;
        if (imgCount > totalImgs) imgCount = 0

        document.getElementById("gallery").src = imageGallery[imgCount];
        return fn;
    }(), 500)
}

function previous() {
    timer = setInterval(function fn() {
        console.log('prev')
        imgCount--;
        if (imgCount < 0) imgCount = totalImgs;
        document.getElementById("gallery").src = imageGallery[imgCount];
        return fn;
    }(), 500)
}

function stopInterval() {
    clearInterval(timer)
}

window.onmouseup = stopInterval;

Demo: http://jsfiddle.net/T42jj/