我正在尝试这个,但它不起作用：
<html> <head> <script src="js/menu-collapser.js" type="text/javascript" media="media screen and (max-width: 599px)"></script> </head> ... </html>
//menu-collapser.js：
jQuery(document).ready(function($){
$('.main-navigation li ul').hide();
$('.main-navigation li').has('ul').click(function() {
$(this).children().toggle();
});
});
您是否知道如何以正确的方式做到这一点？如果标题中直接使用该脚本,则该脚本可以正常工作.
解决方法
你不能直接使用Javascript< script>标签.媒体查询用于链接的CSS文件或内联CSS样式.一个基本的例子：
<link rel="stylesheet" media="screen and (min-width: 900px)" href="desktop.css"/> <link rel="stylesheet" media="screen and (min-width: 571px)" href="tablet.css"/> <link rel="stylesheet" media="screen and (max-width: 570px)" href="mobile.css"/>
或直接在您的样式表中：
@media screen and (max-width: 599px) {
#mobile {
display: block;
}
}
但是,您可以使用外部资产加载器/媒体查询库来执行此操作(require.js,modernizr.js,enquire.js等),在这种情况下,我使用enquire.js设置示例,因为我认为它非常有效且不需要jQuery默认情况下：
完整的例子
<script type="text/javascript" src="/js/enquire.js"></script>
<script type="text/javascript">
// This loads JS files in the head element
function loadJS(url)
{
// adding the script tag to the head
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = url;
// fire the loading
head.appendChild(script);
}
</script>
3)Fire enquire.js并监听媒体查询更改(包括加载和调整大小)：
<script type="text/javascript">
enquire.register("screen and (max-width: 599px)",{
match : function() {
// Load a mobile JS file
loadJS('mobile.js');
}
}).listen();
enquire.register("screen and (min-width: 600px) and (max-width: 899px)",{
match : function() {
// Load a tablet JS file
loadJS('tablet.js');
//console.log('tablet loaded');
}
}).listen();
enquire.register("screen and (min-width: 900px)",{
match : function() {
// Load a desktop JS file
loadJS('desktop.js');
//console.log('desktop loaded');
}
}).listen();
</script>
把它们放在一起
使用从外部文件加载的enquire.js的简单HTML页面：
<html>
<head>
<script type="text/javascript" src="/enquire.js"></script>
<script type="text/javascript">
// This loads JS files in the head element
function loadJS(url)
{
// adding the script tag to the head
var head = document.getElementsByTagName('head')[0];
var script = document.createElement('script');
script.type = 'text/javascript';
script.src = url;
// fire the loading
head.appendChild(script);
}
</script>
<style>
body {
font-family: arial;
}
h1 {
font-size: 50pt;
}
#mobile {
display: none;
}
#tablet {
display: none;
}
#desktop {
display: none;
}
@media screen and (max-width: 599px) {
#mobile {
display: block;
}
}
@media screen and (min-width: 600px) and (max-width: 899px) {
#tablet {
display: block;
}
}
@media screen and (min-width: 900px) {
#desktop {
display: block;
}
}
</style>
</head>
<body>
<div id="desktop">
<h1>Desktop</h1>
</div>
<div id="tablet">
<h1>Tablet</h1>
</div>
<div id="mobile">
<h1>Mobile</h1>
</div>
<script type="text/javascript">
enquire.register("screen and (max-width: 599px)",{
match : function() {
// Load a JS file
loadJS('mobile.js');
}
}).listen();
enquire.register("screen and (min-width: 600px) and (max-width: 899px)",{
match : function() {
loadJS('tablet.js');
//console.log('tablet loaded');
}
}).listen();
enquire.register("screen and (min-width: 900px)",{
match : function() {
loadJS('desktop.js');
//console.log('desktop loaded');
}
}).listen();
</script>
</body>
</html>
除了加载JS文件之外,您还可以创建一个CSS加载器,它可以以相同的方式(有条件地)工作,但是这会破坏在CSS中使用@media的对象.值得一读enquire.js的使用说明,因为它可以比我在这里说明的要多得多.
