490360baa89b5522ed5c7381d7c6081d74b027d8
jcasper
  Wed Nov 18 11:48:12 2020 -0800
Better to use feature detection than browser detection, also this solves a lingering
issue with bowser not being defined on the first pass through in IE 11 (thanks Chris).  No ticket.

diff --git src/hg/js/ajax.js src/hg/js/ajax.js
index b448d00..c913857 100644
--- src/hg/js/ajax.js
+++ src/hg/js/ajax.js
@@ -182,37 +182,32 @@
     var track = getTrack();
     if (track && track.length > 0)
         data = data + "&g=" + track;
     for(var ix=0; ix<names.length; ix++) {
         data = data + "&" + encodeURIComponent(names[ix]) + "=" + encodeURIComponent(values[ix]);
     }
     var type;
     // We prefer GETs so we can analyze logs, but use POSTs if data is longer than a
     // (conservatively small)  maximum length to avoid problems on older versions of IE.
     if ((loc.length + data.length) > 2000) {
         type = "POST";
     } else {
         type = "GET";
     }
 
-    if (typeof bowser === 'undefined') {
-        bowserScript = document.createElement('script');
-        bowserScript.setAttribute('src', 'https://cdnjs.cloudflare.com/ajax/libs/bowser/1.6.1/bowser.min.js');
-        document.head.appendChild(bowserScript);
-    }
 
-    if (!async || (typeof bowser !== 'undefined' && bowser.msie)) {
+    if (!async || (typeof navigator.sendBeacon == 'undefined')) {
         // XmlHttpRequest is used for all synchronous updates and for async updates in IE,
         // because IE doesn't support sendBeacon.  If access to bowser is blocked, the default
         // is to assume the browser is not IE.
         $.ajax({
                    type: type,
                    async: async,
                    url: loc,
                    data: data,
                    trueSuccess: function () {},
                    success: catchErrorOrDispatch,
                    error: errFunc,
                    cache: false
                });
     }
     else {