js 正则匹配 xml 文件头声明
let reg = new RegExp('<\\?xml[^>]*>')
let xmlStr = `<?xml version="1.0" standalone="no"?>`
reg.test(xmlStr) // true
let reg = new RegExp('<\\?xml[^>]*>')
let xmlStr = `<?xml version="1.0" standalone="no"?>`
reg.test(xmlStr) // true