簡單獲取系統版本：

      let webLog = {}
      let userAgent = navigator.userAgent
      // 蘋果手機
      if (userAgent.includes('iPhone') || userAgent.includes('iPad')) {
        // 獲取作業系統版本
        let m1 = userAgent.match(/iPhone OS .*?(?= )/)
        if (m1 && m1.length > 0) {
          let num = m1[0].match(/\d+/g)[0];
          
 
if (parseInt(num) === 9) {
            return true;
          }
        }
      }

全面版本如下：

  // 獲取系統版本
    function getOsVersion() {
      var u = navigator.userAgent, version = ''
      if (u.indexOf('Mac OS X') > -1) {
        // ios
        var regStr_saf = /OS [\d._]*/gi
        var verinfo = u.match(regStr_saf)
        version 
 
= 'IOS' + (verinfo + '').replace(/[^0-9|_.]/ig, '').replace(/_/ig, '.')
      } else if (u.indexOf('Android') > -1 ||
        u.indexOf('Linux') > -1) {
        // android
        version = 'Android' + u.substr(u.indexOf('Android') + 8, u.indexOf(';', u.indexOf('Android')) - u.indexOf('Android') - 8)
      } 
 
else if (u.indexOf('BB10') > -1) {
        // 黑莓bb10系統
        version = 'blackberry' + u.substr(u.indexOf('BB10') + 5, u.indexOf(';', u.indexOf('BB10')) - u.indexOf('BB10') - 5)
      } else if (u.indexOf('IEMobile') > -1) {
        // windows phone
        version = 'winphone' + u.substr(u.indexOf('IEMobile') + 9, u.indexOf(';', u.indexOf('IEMobile')) - u.indexOf('IEMobile') - 9)
      } else {
        var userAgent = navigator.userAgent.toLowerCase()
        if (userAgent.indexOf('windows nt 5.0') > -1) {
          version = 'Windows 2000'
        } else if (userAgent.indexOf('windows nt 5.1') > -1 || userAgent.indexOf('windows nt 5.2') > -1) {
          version = 'Windows XP'
        } else if (userAgent.indexOf('windows nt 6.0') > -1) {
          version = 'Windows Vista'
        } else if (userAgent.indexOf('windows nt 6.1') > -1 || userAgent.indexOf('windows 7') > -1) {
          version = 'Windows 7'
        } else if (userAgent.indexOf('windows nt 6.2') > -1 || userAgent.indexOf('windows 8') > -1) {
          version = 'Windows 8'
        } else if (userAgent.indexOf('windows nt 6.3') > -1) {
          version = 'Windows 8.1'
        } else if (userAgent.indexOf('windows nt 6.2') > -1 || userAgent.indexOf('windows nt 10.0') > -1) {
          version = 'Windows 10'
        } else {
          version = 'Unknown'
        }
      }
      return version
    }