问题描述
我需要这样简单的东西:
i need something easy like this:
<script type="text/javascript">
<!--
if (screen.width <= 699) {
document.location = "mobile.html";
}
//-->
</script>
但不是重定向，我需要将 <script src="js.js"></script> 附加到 <head></头>
but instead of a redirect i'd need <script src="js.js"></script> to be appended in <head></head>
这可能吗?
推荐答案
实际操作:简短演示
你可以定义一个函数，像这样:
You can define a function, like this:
function appendScript(pathToScript) {
var head = document.getElementsByTagName("head")[0];
var js = document.createElement("script");
js.type = "text/javascript";
js.src = pathToScript;
head.appendChild(js);
}
然后用适当的参数调用它(例如根据屏幕大小)，像这样:
And then call it with the appropriate argument (e.g. according to screen size), like this:
appendScript("path/to/file.js");
<小时>
如果您还需要从 head 中删除脚本(例如，基于其 'src' 属性)，您可以定义一个函数，如下所示:
If you also need to remove a script from head (e.g. based on its 'src' attribute), you can define a function, like this:
function removeScript(pathToScript) {
var head = document.getElementsByTagName("head")[0];
var scripts = head.getElementsByTagName("script");
for (var i = 0; i < scripts.length; i++) {
var js = scripts[i];
if (js.src == pathToScript) {
head.removeChild(js);
break;
}
}
}
然后用适当的参数调用它(例如根据屏幕大小)，像这样:
And then call it with the appropriate argument (e.g. according to screen size), like this:
removeScript("path/to/file.js");
<小时>
另外，请注意，使用 screen.width 返回用户屏幕的大小(不是浏览器窗口的宽度).
Also, note that using screen.width returns the size of the user's screen (not the browser-window's width).
如果您需要获取窗口大小，可以使用 $(window).width()(使用 jQuery).如果您想要无 jQuery"解决方案，请查看 this answer 用于跨浏览器的替代方案.
If you need to get the window size you can use $(window).width() (using jQuery).
If you want a "jQuery-free" solution, take a look at this answer for cross-browser alternatives.
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