javascript - 如何定位底部菜单，使其在不同屏幕尺寸下都位于页面底部上方？

Question

我正在努力定位我的菜单，以便它始终在不同尺寸的显示器上保持相同的位置，但在窗口大小减小和增大时也能响应。我绝对不是 CSS 专家，也没有接受过培训，所以我知道我的代码很糟糕。我也试图让菜单逐渐变得轻松，但不确定在哪里输入此代码。非常感谢任何帮助。

.HomeBottomMenu {

    -webkit-font-smoothing:antialiased;
    text-align: center;
    text-align: justify;
    position: absolute;
    bottom: -3em;
}
.HomeBottomMenu ul {

    list-style-type: none;
    margin: 0;
    padding: 0
}

.HomeBottomMenu ul li{

    position: relative;
    line-height: 21px;
    min-width: 220px; 
    text-align: center;
    background: #424242;    
}

.HomeBottomMenu ul li a{

    display: block;
    padding: 8px 8px;
    color: #fff;
    text-decoration:none;
    text-align: left;
    font-family: 'BebasNeueRegular',  Arial, sans-serif;
    font-size: 18px;
    font-weight: bold;
}
.HomeBottomMenu ul li a:hover{

    color: #fff;
    background: #25a0da;
    -webkit-transition: all 0.5s ease-in-out;
    -moz-transition: all 0.5s ease-in-out;
    transition: all 0.5s ease-in-out;
}

.HomeBottomMenu ul li ul.dropdown{

    background: #f2f2f2;
    display: none;
    position: absolute;
    z-index: 999;
    left: -0.01em; 

}
.HomeBottomMenu ul li:hover ul.dropdown{

    display: inline;    
    bottom: 100%;
    position: absolute;
    background: #939393;
    min-height: 50px;
}


.HomeBottomMenu ul li ul.dropdowndropdown {

    position: relative;
    overflow:hidden;
    z-index: 100;
    height:0;
    transition-property: height;
    transition-duration: 0.5s;
    transition-timing-function: linear;
    transition-delay: 0.5s;
    Opacity:1;
}

.HomeBottomMenu ul li ul :hover .dropdowndropdown{

    position: relative;
    display:inline;
    bottom:100%;
    height: 200px;
    Opacity:1;
}

.HomeBottomMenu ul li ul.dropdowndropdown li{

    display: block;
    background-color: rgba(0, 90, 235, 0.33);
    bottom: 100%;
}
.HomeBottomMenu ul li ul.dropdowndropdown li:hover{

    position: relative;
}

.HomeBottomMenu ul li ul.dropdowndropdown li a{

    color:#fff;
    font-size:16px;
    padding: 10px 10px;
    text-align:center;
}

.HomeBottomMenu ul li ul .dropdowndropdown li a :hover{

    color: #fff;
}

Answer 1

Got it working with:

<script type="text/javascript">
    $(window).scroll(function() {
        if ($(this).scrollTop() > 90) {
            $('.HomeBottomMenu').fadeOut(100);
        } else {
            $('.HomeBottomMenu').fadeIn();
        }
    });
</script>

Many thanks for your help.

来自Andy Thomson