Javascript，从`<body>` 中删除类的最快方法
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Javascript, fastest way to remove a class from `<body>`
提问by Alex
I have a body element on which I add a few classes. And I want to remove the no-javascriptclass from it, after it's being read by the browser.
我有一个 body 元素，我在上面添加了一些类。no-javascript在浏览器读取该类之后，我想从中删除该类。
<body class="foo boo no-javascript bla">
<script type="javascript">
// remove no-javascript class here
</script>
回答by Nick Craver
Well, since extra spaces between don't matter, I'd say:
好吧，由于之间的额外空格无关紧要，我会说：
document.body.className = document.body.className.replace("no-javascript","");
回答by Nick Craver
document.querySelector('body').classList.remove('no-javascript');
回答by Stephan Muller
There are no native javascript functions for this, but I always use the following code (borrowed from/inspired by this snipplr
没有针对此的原生 javascript 函数，但我总是使用以下代码（借用/受此snipplr启发）
function removeClass(ele,cls) {
var reg = new RegExp('(\s|^)'+cls+'(\s|$)');
ele.className = ele.className.replace(reg,' ');
}
removeClass(document.getElementById("body"), "no-javascript")
The regex does a better job than the replacefunctions mentioned in other answers, because it checks for the existence of that exact className and nothing more or less. A class named "piano-javascript" would stay intact with this version.
正则表达式比replace其他答案中提到的函数做得更好，因为它检查该确切 className 是否存在，仅此而已。名为“piano-javascript”的类将在此版本中保持不变。
For modern browsers(including IE10 and up) you could also use:
对于现代浏览器（包括 IE10 及更高版本），您还可以使用：
document.querySelector('body').classList.remove('no-javascript');
回答by sje397
document.body.className = '';
回答by darioo
You can avoid all of that work simply by using
您可以通过使用简单地避免所有这些工作
<noscript>Your browser does not support JavaScript!</noscript>
Since whatever you put inside of noscripttag will be shown if Javascript is turned off and nothing will be shown if JS is turned on.
因为noscript如果 Javascript 关闭，您在标签中放置的任何内容都将显示，而如果 JS 打开，则不会显示任何内容。
