jQuery Endless Scrolling loop
<p>I have a project on jsFiddle:</p>

<p><a href="http://jsfiddle.net/willisilliw/aPgPk/" rel="nofollow">jsFiddle Link</a></p>

<p><strong>JavaScript:</strong></p>

<pre><code>var scroller = function() {
    $('#holder div').animate({
        left: ($t.attr('id') == 'prev' ? '-=' : '+=') + 3
    }, 10, 'linear', function() {
        if ($(this).position().left &lt; -$('li:first-child', this).width()) {
            w = $('li:first-child', this).totalWidth();
            $('li:first-child', this).appendTo('ul', this);
            $(this).css('left', $(this).position().left + w);
        }
    });
};

$.fn.extend({
    totalWidth: function() {
        return this.outerWidth() + parseInt(this.css('margin-left'), 10) + parseInt(this.css('margin-right'), 10);
    }
});
wdth = 0;
$('#marquee ul li').each(function() {
    wdth += $(this).totalWidth();
});
$('#holder div').width(wdth);
var to;
$('#prev, #next').css('top', ($('#marquee').outerHeight() - $('#prev').outerHeight()) / 2).live('mousedown mouseup', function(e) {
    $t = $(this);
    if (e.type == 'mousedown') {
        to = setInterval(scroller, 15);
    }
    else {
        clearInterval(to);
    }
});
</code></pre>

<p><strong>HTML:</strong></p>

<pre><code>&lt;div id="marquee"&gt;
    &lt;div id="prev"&gt;&lt;&lt;/div&gt;
    &lt;div id="next"&gt;&gt;&lt;/div&gt;
    &lt;div id="holder"&gt;
        &lt;div&gt;
        &lt;ul&gt;
            &lt;li&gt;Part 1&lt;/li&gt;
            &lt;li&gt;Part 2&lt;/li&gt;
            &lt;li&gt;Part 3&lt;/li&gt;
            &lt;li&gt;Part 4&lt;/li&gt;
            &lt;li&gt;Part 5&lt;/li&gt;
            &lt;li&gt;Part 6&lt;/li&gt;
            &lt;li&gt;Part 7&lt;/li&gt;
            &lt;li&gt;Part 8&lt;/li&gt;
            &lt;li&gt;Part 9&lt;/li&gt;
            &lt;li&gt;Part 10&lt;/li&gt;
        &lt;/ul&gt;
    &lt;/div&gt;
    &lt;/div&gt;
&lt;/div&gt;
</code></pre>

<p><strong>CSS:</strong></p>

<pre><code>* {
    font-family: verdana;
    font-size: 12px;
}
#marquee {
    top: 50px;
    position: relative;
    width: 80%;
    height: 34px;
    background-color: #CCC;
    margin: 0 auto;
    padding: 0;
}
#holder {
    overflow: hidden;
position: absolute;
    left: 5px;
    right: 5px;
    top: 5px;
    bottom: 5px;
}
#holder div {
    position: absolute;
}
#marquee ul li {
    display: inline-block;
    float: left;
    margin-left: 5px;
    padding: 5px 7px;
    background-color: #555;
}
#marquee ul li:nth-child(2n+1) {
background-color: #888;
}
#marquee ul li:first-child {
    margin-left: 0;
}
#prev, #next {
    position: absolute;
    top: 10px;
    background-color: #66F;
    padding: 2px;
    cursor: pointer;
    z-index: 9002;
}
#prev {
    left: -13px;
    border-radius: 5px 0 0 5px;
}
#next {
    right : -13px;
    border-radius: 0 5px 5px 0;
}
</code></pre>

<p>what I am trying to achieve is a scrolling loop on mousedown, stopping on mouseup.</p>

<p>I have been able to make it scroll, and loop but it 'jumps' on every loop change.</p>

<p>Does anyone have any ideas?</p>

<hr>

<p>I have edited the fiddle to remove the CSS rule, also edited the code slightly.</p>

<p>Originally when it scrolled left, it jumped back about 20px and this was made to seem worse by the CSS rule!</p>

<p>Also the animation goes on in 10ms but it loops every 15ms due to the fact that on mouseup the loop would continue for a bit.</p>

<p>The right does not loop because since I did not know how to do the left, I would not waste time making it scroll right erroneously when i could simply make it scroll correctly when it was ready.</p>

<p>I am not using a plugin because I want to learn how to do it myself (stubborn!)</p>
