你可以在setTimeout（非常短暂的超时）中执行警报，因为setTimeout是异步的：

You could do the alert in a setTimeout (which a very short timeout) as setTimeout is asynchronous:

setTimeout("alert('hello world');", 1);

或者为了正确地做到这一点，你真的要在你的setTimeout中使用方法而不是字符串：

Or to do it properly you really show use a method rather than a string into your setTimeout:

setTimeout(function() { alert('hello world'); }, 1);

否则你会打开JavaScript注入攻击。传递字符串时，它将通过JavaScript eval 函数运行。

Otherwise you open yourself up to JavaScript injection attacks. When you pass a string it is run through the JavaScript eval function.