JS method to determine whether scroll bar appears on the page_javascript skills

The example in this article describes the method of JS to determine whether a scroll bar appears on the page. Share it with everyone for your reference. The details are as follows:

var isScroll = function (el) {
   // test targets
   var elems = el ? [el] : [document.documentElement, document.body];
   var scrollX = false, scrollY = false;
   for (var i = 0; i < elems.length; i++) {
     var o = elems[i];
     // test horizontal
     var sl = o.scrollLeft;
     o.scrollLeft += (sl > 0) &#63; -1 : 1;
     o.scrollLeft !== sl && (scrollX = scrollX || true);
     o.scrollLeft = sl;
     // test vertical
     var st = o.scrollTop;
     o.scrollTop += (st > 0) &#63; -1 : 1;
     o.scrollTop !== st && (scrollY = scrollY || true);
     o.scrollTop = st;
   }
   // ret
   return {
     scrollX: scrollX,
     scrollY: scrollY
   };
 };

I hope this article will be helpful to everyone’s JavaScript programming design.