溢出不适用于iPhone和iPad

Question

I'm using this javascript part to hide or no scrollbar when my modal is open or no, but iPhone and iPad don't hide my scroll anyway ? The problem comes from position relative ?

here is my javascript code

function openNav()  {
document.getElementById("myNav").style.cssText = "height:100%";
document.body.style.overflow = "hidden";
}
function closeNav() {
document.getElementById("myNav").style.cssText = "height:0%";
document.body.style.overflow = "scroll";
}

Answer 1

to resolve my problem for the modal I need to add

-webkit-overflow-scrolling:touch

in my CSS file here

*, *:after, *:before {

But the problem still exist when i try to open my fullscreen menu !!