Mouse hover specified element display, display element error

hovers on li, and the last element shows.

    <!DOCTYPE html>
    <html lang="en">
    
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <meta http-equiv="X-UA-Compatible" content="ie=edge">
        <title>Document</title>
        <script src="https://code.jquery.com/jquery-3.1.1.min.js"></script>
        <script>
            $(function () {
                var wrap_len = $("-sharpindex_wrap");
                if (wrap_len.length > 0) {
                    var speed = 800; //
                    var cflul = $(".index_lul");
                    var cflli = $(".index_lli");
                    var cfrli = $(".index_rli");
                    var count = cflli.length;
                    var cflli_h = cflli.outerHeight(true);
                    var cflul_h = cflli_h * count;
                    var cflm_h = $(".index_flcon").outerHeight();
                    var size = Math.ceil(cflul_h / cflm_h);
                    var index = 0;
                    var cur = 0;
                    handle = null;
                    //
                    cflul.css("height", cflul_h);
                    cflli.each(function () {
                        if ($(this).index() % 2 == 0) {
                            $(this).addClass("flli_r0");
                        } else {
                            $(this).addClass("flli_r1");
                        }
                    });
                    cflli.eq(index).addClass("flli_curr");
                    cfrli.eq(index).show();
                    cflli.mouseover(function () {
                        handle = setTimeout(function () {
                            index = $(this.cflli).index();
                            $(this.cflli).addClass("flli_curr").siblings().removeClass("flli_curr");
                            cfrli.eq(index).show().siblings().hide();
                        }, 1000);
                    }).mouseout(function () {
                        clearTimeout(handle);
                    });
                    //
                    function menushow(cur) {
                        cflul.stop(false, true).animate({
                            "margin-top": -cur * cflm_h
                        }, speed);
                    }
                }
            });
        </script>
        <style>
            ul {
                list-style: none;
            }
    
            .flli_r0 {
                background: -sharp999;
            }
    
            .flli_r1 {
                background: -sharp333;
            }
    
            .flli_curr {
                background: -sharpff981f;
            }
    
            .index_lli {
                height: 50px;
                width: 50px;
                float: left;
                margin-right: 5px;
            }
            .index_rli{background: -sharpd9d9d9;display: none;}
        </style>
    </head>
    
    <body>
        <div id="index_wrap">
            <div class="index_flcon">
                <ul class="index_lul">
                    <li class="index_lli">1</li>
                    <li class="index_lli">2</li>
                    <li class="index_lli">3</li>
                    <li class="index_lli">4</li>
                </ul>
                <ul class="index_rul">
                    <li class="index_rli">123</li>
                    <li class="index_rli">234</li>
                    <li class="index_rli">345</li>
                    <li class="index_rli">456</li>
                </ul>
            </div>
        </div>
    </body>
    
    </html>
Apr.19,2021

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