PropertiesChromeCriOSEdgeFirefoxGooglebotIEOperaSafariSamsungBrowser
length 31.0.1650? 12.0.0 50.0.0 2.1.0?? 3.0.0 6.2.0
prototype 31.0.1650? 12.0.0 50.0.0 2.1.0?? 3.0.0 6.2.0
toString 31.0.1650??? 2.1.0?? 4.0.0?