滾動到時更改元素的背景色

Question

我有一個部分，其中包含一些“卡”，其中包含可以單擊的信息。 它們在頁面的中間，我正在嘗試制作，以便在滾動的同時到達它們時它們會改變顏色。 我正在嘗試使用jquery做到這一點，但我有以下內容，但它似乎不起作用：

$(document).ready(function() {
    var eTop = $('.card').offset().top;

    $(window).scroll(function() {
        var position = log(eTop - $(window).scrollTop());
        if (position <= 0) {
            $('.card').css('background-color', 'red');
        }
    });
});

Answer 1

請用

var position = eTop - $(window).scrollTop();

代替

var position = log(eTop - $(window).scrollTop());

請在此處檢查工作片段。

 $(document).ready(function() { var eTop = $('.card').offset().top; $(window).scroll(function() { var position = eTop - $(window).scrollTop(); if (parseInt(position) <= 0) { $('.card').css('background-color', 'red'); } }); }); 

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It was popularised in the 1960s with the release of Letraset sheets containing Lorem Ipsum passages, and more recently with desktop publishing software like Aldus PageMaker including versions of Lorem Ipsum. Why do we use it? It is a long established fact that a reader will be distracted by the readable content of a page when looking at its layout. The point of using Lorem Ipsum is that it has a more-or-less normal distribution of letters, as opposed to using 'Content here, content here', making it look like readable English. Many desktop publishing packages and web page editors now use Lorem Ipsum as their default model text, and a search for 'lorem ipsum' will uncover many web sites still in their infancy. Various versions have evolved over the years, sometimes by accident, sometimes on purpose (injected humour and the like). Where does it come from? Contrary to popular belief, Lorem Ipsum is not simply random text. It has roots in a piece of classical Latin literature from 45 BC, making it over 2000 years old. Richard McClintock, a Latin professor at Hampden-Sydney College in Virginia, looked up one of the more obscure Latin words, consectetur, from a Lorem Ipsum passage, and going through the cites of the word in classical literature, discovered the undoubtable source. Lorem Ipsum comes from sections 1.10.32 and 1.10.33 of "de Finibus Bonorum et Malorum" (The Extremes of Good and Evil) by Cicero, written in 45 BC. This book is a treatise on the theory of ethics, very popular during the Renaissance. The first line of Lorem Ipsum, "Lorem ipsum dolor sit amet..", comes from a line in section 1.10.32. The standard chunk of Lorem Ipsum used since the 1500s is reproduced below for those interested. Sections 1.10.32 and 1.10.33 from "de Finibus Bonorum et Malorum" by Cicero are also reproduced in their exact original form, accompanied by English versions from the 1914 translation by H. Rackham. 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