このプロパティ説明だけど、
firefox 62ではあっさりなくなっているのをガックシと
いろいろ調べると、ようやくわかった。
すでに、firefox64では、消されてしまうらしい。
61にすると面白いことに、
最新でないFirefoxだとChrome ブラウザに変える？と表示する。
こんなFirefoxなら本当に変えたほうが良いかと思うほど、
笑える、つながり。
But it is this property description,
It is very regrettable that firefox 62 is getting worse off
I finally found out, I understood.
It seems that firefox 64 is already erased.
So, to be interesting to the Firefox 61,
It became very fast, memory is also only at the beginning, usually less memory. .
Moreover, the property description can be explicitly used.
Moreover,
Switch to Chrome browser if Firefox is not up-to-date? And display it moderately.
The more I think it is better that changed really, if such Firefox,
Laughable, connected.