I use the following code to check if I can fetch the next page for my infinite scroll feature.

let bottomOfWindow = document.documentElement.scrollTop + window.innerHeight === document.documentElement.offsetHeight;

if (bottomOfWindow) {
    // some logic
}

This works well on desktop browsers but doesn't work on mobile browsers. On debugging, I noticed that the condition doesn't meet because of these values,

document.documentElement.scrollTop;

6580.72705078125

window.innerHeight

1851

document.documentElement.offsetHeight

8432

My questions,

1. Why does this happen on mobile screens alone?
2. If I change the condition to >= document.documentElement.offsetHeight * 0.90, will there be a scenario where even this condition will not satisfy?
3. Is there a more elegant solution?