滚动浏览某个div时如何使粘性导航更改颜色？

时间：2015-04-13 22:29:06

标签： javascript html css

我很好奇当你向下滚动到页面上的特定点或DIV时，如何使粘滞导航栏淡入一种颜色。

我想拥有这个，所以当我滚动到div的末尾或div的开头时，我可以看到白色背景上的白色。

我的一个问题是无法让JS工作，以及将我的背景图像插入到我的css ... header {}中，宽度...我如何仅仅定位徽标（在左边）和右边的导航栏......所以在两个下面出现一个透明条，占据了所需的高度和100％的页面宽度，而不会弄乱背景图像！

同样在codepen中你会注意到改变颜色的标题会出现在主div之下。

这是我的代码...

http://codepen.io/uchmanowicz/pen/qEebbN

谢谢！

HTML 

<!DOCTYPE html>

<html>
<head>
<meta charset="utf-8">
<title>Aesthetic Media</title>
<link href="styles.css" rel="stylesheet" type="text/css"/>
<link href='http://fonts.googleapis.com/css?family=Raleway:400,700,500' rel='stylesheet' type='text/css'>
<script type="text/javascript" src="styles.js"></script>
</head>

<body>

<header>

    <a class="logo" href="#">Aesthetic</a>

    <nav>
        <li><a href="#">Home</a></li>
        <li><a href="#">About</a></li>
        <li><a href="#">Gallery</a></li>
        <li><a href="#">Contact</a></li>
    </nav

    <div class="clears"></div>

    <div class="maintext">

        <h1>We're Aesthetic</h1>
        <h2>A Visual Agency from Niagara</h2>

    </div>

</header>

<main>

<h2 class="whatwedo">Expertise</h2>
<div class="whatwedobox one"><div class="icon"></div><p>Lorem ipsum dolor sit  amet.</p></div>
<div class="whatwedobox two"></div>
<div class="whatwedobox three"></div>

</main>

<footer></footer>

<script   src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.2/jquery.min.js">          </script>
</body>
</html>

CSS 

* {
box-sizing: border-box;
margin: 0px;
padding: 0px;
}

body {
background: white;
}

header {
width: 100%;
height: 550px;
background: white;
background: url('images/main.jpg') center center;
background-size: cover;
padding: 30px 30px 30px 30px;
position: relative;
}

.logo {
position: fixed;
top: 33px;
left: 30px;
width: 200px;
height: 80px;
display: block;
float: left;
z-index: 30;
font-size: 1.8em;
font-weight: 800;
text-decoration: none;
color: #FFFFFF;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
text-transform: uppercase;
font-weight: bold;
letter-spacing: 5px;  
}

.logo a {
font-size: 1.8em;
font-weight: 800;
text-decoration: none;
color: #FFFFFF;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
text-transform: uppercase;
font-weight: bold;
letter-spacing: 5px;
}

nav {
float: right;
z-index: 30;
position: fixed;
top: 20px;
right: 0px;
letter-spacing: .2em;
}

nav li {
float: left;
list-style: none;
padding: 10px 15px 10px 15px;
}

nav li:last-child {
border-right: none;
}

nav li a {
padding: 5px 10px 5px 10px;
color: white;
display: block;
font-weight: 400;
text-decoration: none;
color: #FFFFFF;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
text-transform: uppercase;
-webkit-font-smoothing: antialiased;
}

nav li a:hover {
background-color: rgba(40, 40, 40, 0.5);
-moz-transition: all .3s ease;
-o-transition: all .3s ease;
-ms-transition: all .3s ease;
-transition: all .3s ease;
-webkit-transition: all .3s ease;
-webkit-font-smoothing: antialiased;
}

.clears {
clear: both;
}

.maintext {
margin: auto;
width: 600px;
text-align: center;
margin-top: 200px;
color: white;
z-index: 30;
position: relative;
}

.maintext h1 {
font-weight: 600;
font-size: 1.8em;
line-height: 1.2em;
text-transform: uppercase;
letter-spacing: .1em;
color: #FFFFFF;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
padding-bottom: 15px;
}

.maintext h2 {
font-weight: 400;
font-size: 1.7em;
line-height: 1.2em;
text-transform: uppercase;
letter-spacing: .1em;
text-align: center;
color: #FFFFFF;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
padding-bottom: 15px;
}

main {
max-width: 1180px;
margin: auto;
margin-top: 20px;
overflow: hidden;
}

h2.whatwedo {
text-align: center;
font-weight: 400;
font-size: 1.7em;
line-height: 1.2em;
text-transform: uppercase;
letter-spacing: .1em;
color: #000000;
font-family: 'Raleway' , sans-serif, Helvetica, Verdana;
-webkit-font-smoothing: antialiased;
}

.whatwedobox {
width: 30%;
height: 300px;
border: 1px solid blue;
float: left;
margin-right: 5%;
padding: 20px;
margin-top: 20px;
}

.whatwedobox:last-child {
margin-right: 0%;
}

.icon {
width: 100%;
height: 100px;
background: url(#) no-repeat center center;
}

JS 

$(document).ready(function(){       
var scroll_start = 0;
var startchange = $(".maintext");
var offset = startchange.offset();

 if (startchange.length){
 $(document).scroll(function() { 
  scroll_start = $(this).scrollTop();
  if(scroll_start > offset.top) {
      $("header").css('background-color', '#B5B5B5');
   } else {
      $('header').css('background-color', 'transparent');
   }
});
}
});

1 个答案:

答案 0 :(得分：1)

我认为你的意思是粘性导航栏，当主要内容在滚动时到达时改变背景。请参阅更新的代码和笔演示，如下所示。

$(document).ready(function () {
    var scroll_start = 0;
    var startchange = $(".maintext");
    var offset = startchange.offset();

    if (startchange.length) {
        $(document).scroll(function () {
            scroll_start = $(this).scrollTop();
            if (scroll_start > offset.top) {
                $("nav").css('background-color', 'rgba(0,0,0,.75)');
            } else {
                $('nav').css('background-color', 'transparent');
            }
        });
    }
});
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}
body {
    background: #666;
    min-height: 5000px;
}
header {
    /* background-image: url('images/main.jpg'); */
    background-position: center center;
    background-size: cover;
    position: relative;
}
nav {
    position: fixed;
    width: 100%;
    top: 0;
    right: 0;
    z-index: 1;
    letter-spacing: .2em;
    line-height: 1;
    padding: 30px;
}
nav ul {
    text-align: right;
    list-style: none;
    padding: 0;
    margin: 0;
}
nav li {
    padding: 0 10px;
    display: inline-block;
}
nav li:last-child {
    border-right: none;
}
nav li a {
    padding: 10px;
    color: white;
    display: block;
    font-weight: 400;
    text-decoration: none;
    color: #FFFFFF;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    text-transform: uppercase;
    -webkit-font-smoothing: antialiased;
}
nav li a:hover {
    background-color: rgba(40, 40, 40, 0.5);
    -moz-transition: all .3s ease;
    -o-transition: all .3s ease;
    -ms-transition: all .3s ease;
    -transition: all .3s ease;
    -webkit-transition: all .3s ease;
    -webkit-font-smoothing: antialiased;
}
.logo {
    width: 200px;
    display: block;
    float: left;
    font-size: 1.8em;
    font-weight: 800;
    text-decoration: none;
    color: #FFFFFF;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    text-transform: uppercase;
    font-weight: bold;
    letter-spacing: 5px;
}
.logo a {
    font-size: 1.8em;
    font-weight: 800;
    text-decoration: none;
    color: #FFFFFF;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    text-transform: uppercase;
    font-weight: bold;
    letter-spacing: 5px;
}
.clears {
    clear: both;
}
.maintext {
    padding-top: 90px;
    margin: 200px auto;
    width: 600px;
    text-align: center;
    color: white;
}
.maintext h1 {
    font-weight: 600;
    font-size: 1.8em;
    line-height: 1.2em;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: #FFFFFF;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    padding-bottom: 15px;
}
.maintext h2 {
    font-weight: 400;
    font-size: 1.7em;
    line-height: 1.2em;
    text-transform: uppercase;
    letter-spacing: .1em;
    text-align: center;
    color: #FFFFFF;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    padding-bottom: 15px;
}
main {
    max-width: 1180px;
    margin: auto;
    margin-top: 20px;
    overflow: hidden;
}
.whatwedohd {
    text-align: center;
    font-weight: 400;
    font-size: 1.7em;
    line-height: 1.2em;
    text-transform: uppercase;
    letter-spacing: .1em;
    color: #000000;
    font-family:'Raleway', sans-serif, Helvetica, Verdana;
    -webkit-font-smoothing: antialiased;
}
.whatwedobox {
    width: 30%;
    height: 300px;
    border: 1px solid blue;
    float: left;
    margin-right: 5%;
    padding: 20px;
    margin-top: 20px;
}
.whatwedobox.three {
    margin-right: 0;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<header>
    <nav>
        <a class="logo" href="#">Aesthetic</a>
        <ul>
            <li><a href="#">Home</a></li>
            <li><a href="#">About</a></li>
            <li><a href="#">Gallery</a></li>
            <li><a href="#">Contact</a></li>
        </ul>
    </nav>
    <div class="maintext">
         <h1>We're Aesthetic</h1>
         <h2>A Visual Agency from Niagara</h2>
    </div>
</header>

<main>
    <h2 class="whatwedohd">Expertise</h2>
    <div class="whatwedobox one"></div>
    <div class="whatwedobox two"></div>
    <div class="whatwedobox three"></div>
</main>

<footer></footer>

笔演示： http://codepen.io/anon/pen/qEemdp

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