浏览器判断常用方法

var isOpera = navigator.userAgent.indexOf('Opera') > -1

if (navigator.userAgent.indexOf('Chrome') > -1) {

  return 'chrome'

} else if (navigator.userAgent.indexOf('Firefox') > -1) {

  return 'Firefox'

} else if (!!window.ActiveXObject || 'ActiveXObject' in window) {

  return 'IE'

} else if (navigator.userAgent.indexOf('Safari') > -1) {

 return 'safari'

}