问题
I need to check if browser JavaScript is off, then display a error div instead of the body, how can I do this?
回答1:
<html class="no-js">
<head>
<style>
.error,
.no-js #container {
display: none;
}
.no-js .error {
display: block;
}
</style>
<script>
document.documentElement.className = document.documentElement.className.replace(/\bno-js\b/, '');
</script>
</head>
<body>
<div id="container">
rest of page
</div>
<div class="error">
sorry, no javascripty, no sitey!
</div>
</body>
</html>
Of course, this is usually a bad idea, but I hope you've already considered that.
回答2:
You'll need to do it the other way around - so to speak - you'll have to output everything, and then hide/ remove the error div using Javascript.
It's called Progressive Enhancement.
回答3:
in the body you can add :
<noscript>
Here the html to display when javascript is off
</noscript>
回答4:
@roryf's solution is a good approach, although it is dependent on jQuery, and if the domloaded event fires a little late you can get a 'flash' of the no-js content.
The following will remove the html.no-js class before the body has rendered:
<!DOCTYPE html>
<html class="no-js">
<head>
<script>
if (document.documentElement) {
var cn = document.documentElement.className;
document.documentElement.className = cn.replace(/no-js/,'');
}
</script>
</head>
来源：https://stackoverflow.com/questions/5140388/how-to-detect-if-browser-javascript-is-off-and-display-a-notice