<分区>
我刚刚完成了一个基本的 javasript 程序，我所做的只是将 javascript 声明从 body 之后 移动到 before body 并且 javscript 简单地转向产生错误。据我所知，javascript 不会因声明位置而改变。如果是这样，为什么会出现这种行为？
<!DOCTYPE html>
<html>
<head>
<style>
/* The Modal (background) */
.modal {
display: none; /* Hidden by default */
position: fixed; /* Stay in place */
z-index: 1; /* Sit on top */
padding-top: 100px; /* Location of the box */
left: 0;
top: 0;
width: 100%; /* Full width */
height: 100%; /* Full height */
overflow: auto; /* Enable scroll if needed */
background-color: rgb(0,0,0); /* Fallback color */
background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}
/* Modal Content */
.modal-content {
position: relative;
background-color: #fefefe;
margin: auto;
padding: 0;
border: 1px solid #888;
width: 80%;
box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
-webkit-animation-name: animatetop;
-webkit-animation-duration: 0.4s;
animation-name: animatetop;
animation-duration: 0.4s
}
/* Add Animation */
@-webkit-keyframes animatetop {
from {top:-300px; opacity:0}
to {top:0; opacity:1}
}
@keyframes animatetop {
from {top:-300px; opacity:0}
to {top:0; opacity:1}
}
/* The Close Button */
.close {
color: white;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: #000;
text-decoration: none;
cursor: pointer;
}
.modal-header {
padding: 2px 16px;
background-color: #5cb85c;
color: white;
}
.modal-body {padding: 2px 16px;}
.modal-footer {
padding: 2px 16px;
background-color: #5cb85c;
color: white;
}
</style>
</head>
<body>
<h2>Animated Modal with Header and Footer</h2>
<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<div class="modal-header">
<span class="close">×</span>
<h2>Modal Header</h2>
</div>
<div class="modal-body">
<p>Some text in the Modal Body</p>
<p>Some other text...</p>
</div>
<div class="modal-footer">
<h3>Modal Footer</h3>
</div>
</div>
</div>
<script>
// Get the modal
var modal = document.getElementById('myModal');
// Get the button that opens the modal
var btn = document.getElementById("myBtn");
// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];
// When the user clicks the button, open the modal
btn.onclick = function() {
modal.style.display = "block";
}
// When the user clicks on <span> (x), close the modal
span.onclick = function() {
modal.style.display = "none";
}
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
if (event.target == modal) {
modal.style.display = "none";
}
}
</script>
</body>
</html>
我所做的简单代码更改...
<!DOCTYPE html>
<html>
<head>
<style>
/* The Modal (background) */
.modal {
display: none; /* Hidden by default */
position: fixed; /* Stay in place */
z-index: 1; /* Sit on top */
padding-top: 100px; /* Location of the box */
left: 0;
top: 0;
width: 100%; /* Full width */
height: 100%; /* Full height */
overflow: auto; /* Enable scroll if needed */
background-color: rgb(0,0,0); /* Fallback color */
background-color: rgba(0,0,0,0.4); /* Black w/ opacity */
}
/* Modal Content */
.modal-content {
position: relative;
background-color: #fefefe;
margin: auto;
padding: 0;
border: 1px solid #888;
width: 80%;
box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2),0 6px 20px 0 rgba(0,0,0,0.19);
-webkit-animation-name: animatetop;
-webkit-animation-duration: 0.4s;
animation-name: animatetop;
animation-duration: 0.4s
}
/* Add Animation */
@-webkit-keyframes animatetop {
from {top:-300px; opacity:0}
to {top:0; opacity:1}
}
@keyframes animatetop {
from {top:-300px; opacity:0}
to {top:0; opacity:1}
}
/* The Close Button */
.close {
color: white;
float: right;
font-size: 28px;
font-weight: bold;
}
.close:hover,
.close:focus {
color: #000;
text-decoration: none;
cursor: pointer;
}
.modal-header {
padding: 2px 16px;
background-color: #5cb85c;
color: white;
}
.modal-body {padding: 2px 16px;}
.modal-footer {
padding: 2px 16px;
background-color: #5cb85c;
color: white;
}
</style>
</head>
<script>
// Get the modal
var modal = document.getElementById('myModal');
// Get the button that opens the modal
var btn = document.getElementById("myBtn");
// Get the <span> element that closes the modal
var span = document.getElementsByClassName("close")[0];
// When the user clicks the button, open the modal
btn.onclick = function() {
modal.style.display = "block";
}
// When the user clicks on <span> (x), close the modal
span.onclick = function() {
modal.style.display = "none";
}
// When the user clicks anywhere outside of the modal, close it
window.onclick = function(event) {
if (event.target == modal) {
modal.style.display = "none";
}
}
</script>
<body>
<h2>Animated Modal with Header and Footer</h2>
<!-- Trigger/Open The Modal -->
<button id="myBtn">Open Modal</button>
<!-- The Modal -->
<div id="myModal" class="modal">
<!-- Modal content -->
<div class="modal-content">
<div class="modal-header">
<span class="close">×</span>
<h2>Modal Header</h2>
</div>
<div class="modal-body">
<p>Some text in the Modal Body</p>
<p>Some other text...</p>
</div>
<div class="modal-footer">
<h3>Modal Footer</h3>
</div>
</div>
</div>
</body>
</html>