更改元刷新的内容不会改变刷新时间 [英] Changing the content of meta refresh does not change refreshing time
问题描述
在< head> 中有一个 meta http-equiv =refresh。
<head>
<meta name="mymeta" http-equiv="refresh" content="2" id="myMeta">
</head>
使用 Javascript ，我试图改变<$ c $这个 meta 标记的c> content 属性。
Using Javascript, I'm trying to change the content attribute of this meta tag.
var myMeta = document.getElementById("myMeta");
myMeta.content="10";
当我通过 document.write（myMeta.content）显示内容时; ，我得到的值是 10 ，但是， meta 标签会每次刷新 2 。
When I display the content via document.write(myMeta.content);, I get the changed value which is 10, however, the meta tag will keep refreshing each 2 seconds.
我已经在Firefox和Opera中测试了这个功能。
I have tested this both in Firefox and Opera.
FULL PAGE
<!DOCTYPE html>
<html>
<head>
<meta name="mymeta" http-equiv="refresh" content="2" id="myMeta">
<script>
var myMeta=document.getElementById("myMeta");
myMeta.content="10";
document.write(myMeta.content);
</script>
</head>
<body>
</body>
</html>
推荐答案
这是因为浏览器立即处理< meta> 标记。
This happens because the browser immediately process the <meta> tag when it is present onload.
请参阅 DEMO 。
当文档被加载时，浏览器会看到并处理以下内容：
When the document is being loaded, the browser sees and processes the following:
<meta name="mymeta" http-equiv="refresh" content="2" id="myMeta"/>
尽管您尝试将其内容从2更改为10，但2秒刷新已被确认，浏览器在刷新页面之前等待2秒钟。由JavaScript注入的10秒刷新实际上工作*，尽管页面在2秒内刷新并且没有任何事情发生。然后再重复这个过程。
Even though you try to change its content from 2 to 10, that 2 second refresh is already acknowledged and the browser waits for 2 seconds before it refreshes the page. The 10-second refresh that is injected by JavaScript actually works*, although the page has been refreshed by the time it reaches 2 seconds and nothing seems to happen. This process is then repeated again and again.
试试在，看看会发生什么。
Try the opposite and see what happens.
*这只适用于Safari和Chrome。 Firefox和Opera不支持通过JavaScript修改元刷新。
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