Question

我有下一个代码，当滚动到达类.ua时，我需要的是显示警报。但什么都没发生。我还检查了脚本的路线，像.addClass这样的东西完美无缺。

$(document).ready(function() {

	$('.ua').waypoint(function() {
  		alert('Top of header hit top of viewport.');
	});

});

<!DOCTYPE html>
<html>
<head>
	<title></title>
	<meta charset="UTF-8">
 	<meta name="viewport" content="width=device-width, initial-scale=1.0">
	<title>First one</title>
	<link rel="stylesheet" type="text/css" href="css/grid.css">
	<link rel="stylesheet" href="http://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.min.css">
	<link rel="stylesheet" type="text/css" href="css/style.css">
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
</head>
<body>
	<nav class="main-nav">
		
	</nav>
	<div class="main-div">
		
	</div>
	<div class="ua">
		<h1>HOLAA</h1>
	</div>
<script src="jq/jq.js"></script>
</body>
</html>

Answer 1

您需要在结束head标记

之前添加路标jQuery插件

<script src="https://cdnjs.cloudflare.com/ajax/libs/waypoints/4.0.0/jquery.waypoints.js"></script>

＆＃13;

$(document).ready(function() {

	$('.ua').waypoint(function() {
  		alert('Top of header hit top of viewport.');
	});

});

＆＃13;

	<link rel="stylesheet" type="text/css" href="css/grid.css">
	<link rel="stylesheet" href="http://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.4.0/css/font-awesome.min.css">
	<link rel="stylesheet" type="text/css" href="css/style.css">
	<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.12.2/jquery.min.js"></script>
  <script src="https://cdnjs.cloudflare.com/ajax/libs/waypoints/4.0.0/jquery.waypoints.js"></script>

	<nav class="main-nav">
		
	</nav>
	<div class="main-div">
		
	</div>
	<div class="ua">
		<h1>HOLAA</h1>
	</div>
<script src="jq/jq.js"></script>

＆＃13;

Answer 2

无需使用插件。看看这有多容易：

＆＃13;

pastit = false;
wayloc = $('.ua').position().top;

$(window).scroll(function(){
  pos = $(window).scrollTop();
  $('#msg').html(pos); //UNNECESSARY - For Demo Only
  if ( !pastit && pos > 500){
    pastit = true;
    $('body').css('background','palegreen');
  }else if (pastit && pos < 500){
    pastit = false;
        $('body').css('background','white');
  }
});

// Necessary for stack snippets window to work Full Screen
$(window).resize(function(){
  wayloc = $('.ua').position().top;
});

＆＃13;

html,body{min-height:2000px;}
.main-nav{width:100vw;height:250px;}
.main-div{width:100vw;height:500px;}
.ua {width:100vw;height:30px;background:wheat;border:1px solid orange;}

/* Unnecessary - For Demo Only */
#msg{position:fixed;top:50px;left:70%;padding:10px;min-width:50px;text-align:center;background:wheat;border:1px solid orange;}

＆＃13;

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>

<div id="msg"></div><!-- Unnecessary For Demo Only-->

<nav class="main-nav"></nav>
<div class="main-div"></div>

<div class="ua">
  <h1>HOLAA</h1>
</div>

＆＃13;

Jquery .waypoint无法正常工作

2 个答案: