如何在没有jQuery的JavaScript中在元素之前插入HTML？
问题描述：
如何在纯JavaScript中重写此jQuery操作：
How can I rewrite this jQuery operation in pure JavaScript:
$("#my_id").before('<span class="asterisk">*</span>');
答
这将做你想要的，而不需要支持任何膨胀的库，如jQuery。
This will do what you want, without needing the support of any bloated libraries like jQuery.
var my_elem = document.getElementById('my_id');
var span = document.createElement('span');
span.innerHTML = '*';
span.className = 'asterisk';
my_elem.parentNode.insertBefore(span, my_elem);