Fixed Positioning in Mobile Safari: A Comprehensive Guide

Achieving fixed positioning for an element relative to the viewport in Mobile Safari can be challenging. Despite the widespread belief that "position: fixed" does not work in Mobile Safari, Gmail has introduced an innovative solution that offers a close approximation of true fixed positioning.

One approach to tackle this problem is to leverage JavaScript to detect real-time scroll events. This allows you to dynamically adjust the position of an element as the page is scrolled.

To achieve a fixed position div that scrolls to the bottom of the page, you can implement a simple JavaScript script:

window.onscroll = function() {
  var fixedDiv = document.getElementById('fixedDiv');
  fixedDiv.style.top = (window.pageYOffset   window.innerHeight - 25)   'px';
};

By adjusting the "top" property of the "fixedDiv" element based on the page's offset and height, the div will maintain its position at the bottom of the viewport as the user scrolls. The "25" adjustment ensures that the div is slightly offset from the bottom of the screen for optimal viewing.