正则踩坑一
$1,$2.....:显示括号里的第一个;显示括号里的第二个....
let content='<img src="http://qiniu.ve-link.com/files/3/3/45/b20e446593872e59a99aff02edca5c9a450e4533.jpg" style="height:200rpx"/>'
content=content.replace(/<img([\s\w"-=\/\.:;]+)(?:(style="[^"]+"))/g, '<img$2')
console.log(content) //<imgstyle="height:200rpx"/>
content=content.replace(/<img([\s\w"-=\/\.:;]+)(?:(style="[^"]+"))/g, '<img$1')
console.log(content) //<img src="http://qiniu.ve-link.com/files/3/3/45/b20e446593872e59a99aff02edca5c9a450e4533.jpg" />