javascript - 修复了 div 上的导航效果

Question

我找到了这段代码。

   $(document).ready(function(){
	   $(window).bind('scroll', function() {
	   var navHeight = $( window ).height() - 70;
			 if ($(window).scrollTop() > navHeight) {
				 $('nav').addClass('fixed');
			 }
			 else {
				 $('nav').removeClass('fixed');
			 }
		});
	});

/*
Tutorial Name: Scroll To Top Then Fixed Navigation Effect With JQuery and CSS
Description: Create a sticky navigation bar that remains fixed to the top after scroll
Author: Stanislav Kostadinov
Author URI: http://stanislav.it
Version: 1.0.0 - 11.01.2014
*/

* {margin: 0; padding: 0;}

a {text-decoration: none;}

/* This class is added on scroll */
.fixed {
	position: fixed; 
	top: 0; 
	height: 70px; 
	z-index: 1;
}

body {
	color: #fff;
	font-family: 'open-sans-bold'; 
	font-size: 18px;
	text-align: center;
}

/* Font Face Settings */
@font-face {
    font-family: 'open-sans-bold';
	src: url('../fonts/open-sans/OpenSans-Bold.eot');
    src: url('../fonts/open-sans/OpenSans-Bold.eot?iefix') format('embedded-opentype'),
		 url('../fonts/open-sans/OpenSans-Bold.ttf');
    font-weight: normal;
}	

/* Navigation Settings */
nav {
	position: absolute;
	bottom: 0;
	width: 100%;
	height: 70px;
	background: #fff;
}

nav li {
	display: inline-block;
	padding: 24px 10px;
}

nav li a {
	color: #757575;
	text-transform: uppercase;
}

section {
	height: 100vh;
}

/* Screens Settings */
#screen1 {	
	background: #43b29d;
}

#screen1 p {
	padding-top: 200px;
}

#screen2 {
	background: #efc94d;
}

#screen3 {
	background: #e1793d;
}

@media only screen and (max-width: 520px) {

	nav li {
		padding: 24px 4px;
	}

	nav li a {
		font-size: 14px;
	}

}

<section id="screen1">

	<p>Scroll down</p>

	<nav>
		<ul>
			<li><a href="#">Home</a></li>
			<li><a href="#">About</a></li>
			<li><a href="#">Services</a></li>
			<li><a href="#">Team</a></li>
			<li><a href="#">Contact</a></li>
		</ul>
	</nav>

</section>
	
<section id="screen2"></section>
<section id="screen3"></section>

这是一个工作示例。 http://stanhub.com/tutorials/sticky-navigation/

它是一个粘性菜单并且运行良好，但问题是它只有在页面完全向下滚动时才会粘住。 nav div 向下滚动 40px 后是否可以修复它？可以说它在导航框和顶部浏览器之间有 40 像素。

Answer 1

是的，改变代码中的一个变量 var navHeight = $( window ).height() - 70;

到 var navHeight = $( window ).height() - 40;

这应该可以解决指定高度的问题