根据滚动更改导航栏上的RGBA背景颜色 [英] Changing rgba background color on navbar based on scroll

问题描述

我的页面顶部有一个bootstrap固定导航栏.我想根据页面上的滚动位置将背景颜色的不透明度从0逐渐逐渐提高到0.75.如何使用jquery做到这一点?

I've got a bootsrap fixed navbar at the top of my page. I'd like to gradually and smoothly increase the background-color opacity from 0 up to 0.75 based on the scroll position on the page. How can I do this using jquery?

滚动之前

.navbar-inverse {
  background: rgba(53,145,204,0);
}

滚动后〜500px或更好，但仍为当前窗口大小的100％

after scroll ~500px or better yet 100% of current window size

.navbar-inverse {
  background: rgba(53,145,204,0.75);
}

推荐答案

使用它来达到类似的效果:

Used this to achieve a similar effect:

    $(function() {
        //caches a jQuery object containing the header element
        var header = $(".fade-transparent");
        $(window).scroll(function() {
            var scroll = $(window).scrollTop();

            if (scroll >= 200) {
                header.removeClass('fade-transparent').addClass("fade-background");
            } else {
                header.removeClass("fade-background").addClass('fade-transparent');
            }
        });
    });


.fade-background {

      background-color: #3591cc;
      background-color: rgba(53,145,204,0.75);

      -webkit-transition: background-color 3s;
    transition: background-color 3s;

}

.fade-transparent {

      background-color: transparent;

      -webkit-transition: background-color 1s;
    transition: background-color 1s;

}

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