jQueryを使用して固定位置のDivをコンテンツとともに水平方向にスクロールさせる方法は?

<code class="css">.scroll_fixed {
    position: absolute;
    top: 210px;
}

.scroll_fixed.fixed {
    position: fixed;
    top: 0;
}</code>

<code class="javascript">// Retrieve the initial left offset
var leftInit = $(".scroll_fixed").offset().left;

// Get the top offset of the div
var top = $('.scroll_fixed').offset().top - parseFloat($('.scroll_fixed').css('margin-top').replace(/auto/, 0));


$(window).scroll(function(event) {
    // Calculate the horizontal scroll position
    var x = 0 - $(this).scrollLeft();

    // Calculate the vertical scroll position
    var y = $(this).scrollTop();

    // Position the div based on scroll
    // Horizontally: Left margin of the initial position minus the horizontal scroll position
    // Vertically: Top margin of the initial position minus the vertical scroll position
    if (y >= top) {
        // Display the div at the top of the viewport
        $('.scroll_fixed').addClass('fixed');
    } else {
        // Remove the 'fixed' class from the div
        $('.scroll_fixed').removeClass('fixed');
    }

    $(".scroll_fixed").offset({
        left: x + leftInit,
        top: y
    });

});</code>