要兼容 IE 就需要这段代码，
Content 是说当下要用那个游览器的功能，一下是设置内容
"IE=edge"
"IE=11"
"IE=EmulateIE11"
"IE=10"
"IE=EmulateIE10"
"IE=9"
"IE=EmulateIE9
"IE=8"
"IE=EmulateIE8"
"IE=7"
"IE=EmulateIE7"
"IE=5"
<meta http-equiv="X-UA-Compatible" content="IE=Edge,chrome=1">
chrome=1 是给 IE 游览器的 JavaScript 引擎加速，不过前提是必须先装 chrome plugin
Links:
1. https://*.com/questions/6771258/what-does-meta-http-equiv-x-ua-compatible-content-ie-edge-do