摘要：
我们常用的script标签，有两个和性能、js文件下载执行相关的属性：defer和asyncdefer的含义【摘自https://developer.mozilla.org/En/HTML/Element/Script】This Boolean attribute is set to indicate to a browser that the script is meant to be executed after the document has been parsed.async的含义【摘自https://developer.mozilla.org/En/HTML/Element/Scr 阅读全文