Use the font-size of the element if the font-size of the parent is 0 and use 16 if both are 0 (applies when deltaMode is 1).

Author: brandonaaron

ChangeLog.md

@@ -1,5 +1,9 @@
 # Mouse Wheel ChangeLog
 
+## 3.1.12
+
+* Fix possible 0 value for line height when in delta mode 1
+
 ## 3.1.11
 
 * Fix version number for package managers...

jquery.mousewheel.js

@@ -61,11 +61,12 @@
  },
 
  getLineHeight: function(elem) {
- var $parent = $(elem)['offsetParent' in $.fn ? 'offsetParent' : 'parent']();
+ var $elem = $(elem),
+ $parent = $elem['offsetParent' in $.fn ? 'offsetParent' : 'parent']();
  if (!$parent.length) {
  $parent = $('body');
  }
- return parseInt($parent.css('fontSize'), 10);
+ return parseInt($parent.css('fontSize'), 10) || parseInt($elem.css('fontSize'), 10) || 16;
  },
 
  getPageHeight: function(elem) {