add updateBrowserURL config var that controls whether JBrowse updat…

…es the browser URL continuously with the share url

index.html

@@ -40,7 +40,8 @@
                                            initialHighlight: queryParams.highlight,
                                            show_nav: queryParams.nav,
                                            show_tracklist: queryParams.tracklist,
-                                           show_overview: queryParams.overview
+                                           show_overview: queryParams.overview,
+                                           updateBrowserURL: true
                                        });
         });
     </script>

release-notes.txt

@@ -1,5 +1,10 @@
 {{$NEXT}}
 
+ * By default, JBrowse now continuously updates the browser's URL bar
+   to contain a URL that will show the current JBrowse view directly.
+   This is enabled by default only if JBrowse is running from the
+   default index.html included in the JBrowse distribution.
+
  * HTMLFeatures tracks now accept `style->label` and
    `style->description` configuration variables variable that can be
    set to a function callback that returns a string with the feature's

src/JBrowse/Browser.js

@@ -1747,7 +1747,7 @@ Browser.prototype.makeShareLink = function () {
     // connect moving and track-changing events to update it
     var updateShareURL = function() {
         shareURL = browser.makeCurrentViewURL();
-        if( window.history && window.history.replaceState )
+        if( browser.config.updateBrowserURL && window.history && window.history.replaceState )
             window.history.replaceState( {},"", shareURL );
     };
     dojo.connect( this, "onCoarseMove",                     updateShareURL );