Can't not scroll to top after trigger the keyboard by click input or textarea

1

Can’t not scroll to top after trigger the keyboard by click input or textarea. The paltform is IOS, any one have the same sutiation?

Begin:

Then:

Now can’t scroll to the top…

2

I found this solution works:

<meta name="viewport" content="width=device-width, height=device-height, initial-scale=1.0, maximum-scale=1.0, target-densityDpi=device-dpi" />

But I don’t know how it works…