Question

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。

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');
   }
});
}
});

Answer 1

您可以将$(window).scrollTop()与该div的offset().top进行比较。 offset()是method，而非property。因此，调用offset()将同时返回top和left。

if($(window).scrollTop()>=$("that_div").offset().top) {
   //do something here
}

在您的代码中，尝试替换

行

var offset = startchange.offset;

与

var offset = startchange.offset();

当您滚动到所需的div时，如何使粘性导航栏更改颜色？

1 个答案: