Using Background-Attachment:Fixed in Safari on The Ipad

How to replicate background-attachment fixed on iOS

It has been asked in the past, apparently it costs a lot to mobile browsers, so it's been disabled.

Check this comment by @PaulIrish:

Fixed-backgrounds have huge repaint cost and decimate scrolling performance, which is, I believe, why it was disabled.

you can see workarounds to this in this posts:

Fixed background image with ios7

Fixed body background scrolls with the page on iOS7

Background Attachments have been disabled in mobile browsers.

Change background-attachment to something like background-size: cover.

For more information:

How to replicate background-attachment fixed on iOS

From the post:

Check this comment by @PaulIrish:

Fixed-backgrounds have huge repaint cost and decimate scrolling
performance, which is, I believe, why it was disabled.