Fix for zooming in iOS 11.3

[Matt Parizeau]

iOS 11.3 broke a number of libraries and web apps by changing touch event handlers to be passive by default. WebViewer 3.2 includes a workaround for this change but if you're using an older version you can patch MobileReaderControl.js to fix the issue.

Find the code block in MobileReaderControl.js that starts with document.ontouchmove = ... and replace it with the following:

document.addEventListener('touchmove', function(e) {
  if (!$.mobile.activePage.hasClass('custom-dialog') || (e.scale && e.scale !== 1)) {
    e.preventDefault();
  }
}, { passive: false });