PropertiesChromeCriOSEdgeFirefoxGooglebotIEOperaSafariSamsungBrowser
length 41.0.2272? 12.0.0 50.0.0??? 3.0.0 4.0.0
prototype 41.0.2272? 12.0.0 50.0.0??? 3.0.0 4.0.0
toString 43.0.2357??????? 4.0.0