嘿我正在尝试为我的nav元素添加一个类和一个属性，由于某种原因我的代码跳转到else语句。感谢任何帮助。
这是我的Html
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1">
<!-- The above 3 meta tags *must* come first in the head; any other head content must come *after* these tags -->
<title>Portfolio</title>
<!-- Bootstrap -->
<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="css/style.css" rel="stylesheet">
<link href='https://fonts.googleapis.com/css?family=Poppins:400,300,500,600,700' rel='stylesheet' type='text/css'>
<link href='https://fonts.googleapis.com/css?family=Oswald:400,300' rel='stylesheet' type='text/css'>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/font-awesome/4.6.2/css/font-awesome.min.css">
<!-- Content Filter -->
<link href='http://fonts.googleapis.com/css?family=Open+Sans:400,300,600,700' rel='stylesheet' type='text/css'>
<link rel="stylesheet" href="css/styleC.css"> <!-- Resource style -->
<script src="js/modernizr.js"></script> <!-- Modernizr -->
<!-- HTML5 shim and Respond.js for IE8 support of HTML5 elements and media queries -->
<!-- WARNING: Respond.js doesn't work if you view the page via file:// -->
<!--[if lt IE 9]>
<script src="https://oss.maxcdn.com/html5shiv/3.7.2/html5shiv.min.js"></script>
<script src="https://oss.maxcdn.com/respond/1.4.2/respond.min.js"></script>
<![endif]-->
</head>
<body>
<div class="pageone">
<header>
<nav class="navbar navbar-default navbar-fixed-top">
<div class="container-fluid">
<!-- Brand and toggle get grouped for better mobile display -->
<div class="navbar-header">
<button type="button" class="navbar-toggle collapsed" data-toggle="collapse" data-target="#bs-example-navbar-collapse-1" aria-expanded="false">
<span class="sr-only">Toggle navigation</span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
<span class="icon-bar"></span>
</button>
<a class="navbar-brand" href="#"><img id="logo" src="images/Logo.png" alt="logo"></a>
</div>
<!-- Collect the nav links, forms, and other content for toggling -->
<div class="collapse navbar-collapse" id="bs-example-navbar-collapse-1">
<ul class="nav navbar-nav">
<li class="active"><a href="#">HOME <span class="sr-only">(current)</span></a></li>
<li><a href="#">WORK</a></li>
<li><a href="#">ABOUT ME</a></li>
</ul>
<ul class="nav navbar-nav navbar-right">
<li><a href="#">CONTACT</a></li>
</ul>
</div><!-- /.navbar-collapse -->
</div><!-- /.container-fluid -->
</nav>
</header>
<div class="container">
<div class="jumbotron">
<h1>Hy, I’m Robert and I am a webdesigner based in Aarhus.</h1>
</div>
</div>
</div>
<div id="2" class="pagetwo">
<div class="container-fluid">
<main class="cd-main-content">
<div class="cd-tab-filter-wrapper">
<div class="cd-tab-filter">
<ul class="cd-filters">
<li class="placeholder">
<a data-type="all" href="#0">All</a> <!-- selected option on mobile -->
</li>
<li class="filter"><a class="selected" href="#0" data-type="all">All</a></li>
<li class="filter" data-filter=".color-1"><a href="#0" data-type="color-1">Constructing Architecture</a></li>
<li class="filter" data-filter=".color-2"><a href="#0" data-type="color-2">Photography</a></li>
<li class="filter" data-filter=".color-2"><a href="#0" data-type="color-2">Multimedia Design</a></li>
</ul> <!-- cd-filters -->
</div> <!-- cd-tab-filter -->
</div> <!-- cd-tab-filter-wrapper -->
<section class="cd-gallery">
<ul>
<li class="mix color-1 check1 radio2 option3"><img src="img/img-1.jpg" alt="Image 1"></li>
<li class="mix color-2 check2 radio2 option2"><img src="img/img-2.jpg" alt="Image 2"></li>
<li class="mix color-1 check3 radio3 option1"><img src="img/img-3.jpg" alt="Image 3"></li>
<li class="mix color-1 check3 radio2 option4"><img src="img/img-4.jpg" alt="Image 4"></li>
<li class="mix color-1 check1 radio3 option2"><img src="img/img-5.jpg" alt="Image 5"></li>
<li class="mix color-2 check2 radio3 option3"><img src="img/img-6.jpg" alt="Image 6"></li>
<li class="mix color-2 check2 radio2 option1"><img src="img/img-7.jpg" alt="Image 7"></li>
<li class="mix color-1 check1 radio3 option4"><img src="img/img-8.jpg" alt="Image 8"></li>
<li class="mix color-2 check1 radio2 option3"><img src="img/img-9.jpg" alt="Image 9"></li>
<li class="mix color-1 check3 radio2 option4"><img src="img/img-10.jpg" alt="Image 10"></li>
<li class="mix color-1 check3 radio3 option2"><img src="img/img-11.jpg" alt="Image 11"></li>
<li class="mix color-2 check1 radio3 option1"><img src="img/img-12.jpg" alt="Image 12"></li>
<li class="gap"></li>
<li class="gap"></li>
<li class="gap"></li>
</ul>
<div class="cd-fail-message">No results found</div>
</section> <!-- cd-gallery -->
</div>
</div>
<div class="pagethree">
<div class="container-fluid">
<div class="row">
<div class="col-xs-12">
<h2 class="text-center about-txt"><a id="3" href="#">About Me</a></h2>
<img src="images/Profile-image.png" class="img-responsive img-rounded center-block" alt="My Face :)">
</div>
</div>
<div class="row">
<div class="col-sm-12">
<p class="text-center about">To tell you a little more about me, I have decided to make this short
personal description. I love doing many things: design, photography, architecture, coffee
and all of these traits represent me. I thrive in a social environment, loving the interaction between
co-workers and clients. People say I’m funny and this makes working with me an ease.</p>
</div>
</div>
</div>
</div>
<div class="pagefour">
<div class="container-fluid">
<div class="row">
<div class="col-sm-12">
<div class="jumbotron">
<h2>Feel free to contact me at <span>info@freirobert.com</span></h2>
</div>
</div>
</div>
<div class="row">
<div class="col-sm-12">
<p>You can also find me on social media on the links below</p>
</div>
</div>
<div class="row">
<div class="col-sm-12">
<a href="#"><i class="fa fa-linkedin-square fa-2x" aria-hidden="true"></i></a>
<a href="#"><i class="fa fa-instagram fa-2x" aria-hidden="true"></i></a>
<a href="#"><i class="fa fa-behance-square fa-2x" aria-hidden="true"></i></a>
</div>
</div>
</div>
</div>
<div class="footer">
<div class="container-fluid">
<p class="text-center">©Robert Frei 2016</p>
</div>
</div>
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.3/jquery.min.js"></script>
<!-- Include all compiled plugins (below), or include individual files as needed -->
<script src="js/bootstrap.min.js"></script>
<!-- Resource Content Filter -->
<script src="js/jquery-2.1.1.js"></script>
<script src="js/jquery.mixitup.min.js"></script>
<script src="js/main.js"></script> <!-- Resource jQuery -->
<script src="js/add.js"></script>
</body>
</html>
所需物品的css
.pagetwo {
background-color: white;
background-size: cover;
}
.darkNav {
background-color: black !important;
}
我的JS无效......
$(function () {
var header = $('.navbar-default .navbar-toggle .icon-bar');
var logo = $('#logo');
var hieghtThreshold = $(".pagetwo").offset().top;
var hieghtThreshold_end = $(".pagetwo").offset().top + $(".pagetwo").height();
$(window).scroll(function() {
var scroll = $(window).scrollTop();
if (scroll >= hieghtThreshold && scroll <= hieghtThreshold_end ) {
console.log("WORKS!!!!!");
//logo.attr("src","/images/Logo-black.png");
//header.addClass("darkNav");
} else {
alert("IT BROKE!");
//logo.attr("src","/images/Logo.png");
//header.removeClass("darkNav");
}
});
})
答案 0 :(得分：3)
每次滚动窗口时都会执行此操作。转到魔术阈值，看到WORKS!!!!!评论出现在控制台中。用alert()替换console.log()将会很好地说明它。
滚动页面时，$(window).scroll()会不断触发。因此，由于您使用了alert()，因此每次滚动时都会一直触发，并向您显示BROKE!。