Added download attribute check for IE11 (#22)

* Added download attribute check for IE11

* Added comment for clarity

* Added release note to changelog

Author: grneggandsam

CHANGELOG.md

@@ -1,5 +1,7 @@
 Next Release
 -------------
+* Added download attribute check for IE11 in unload trigger.
+
 1.5.0
 ------
 * Added support for calculating height of body containing absolute positioned elements.

src/provider/application.js

@@ -260,6 +260,10 @@ class Application extends EventEmitter {
   }
 
   unload() {
+    // Need this line because IE11 & some safari trigger onbeforeunload despite presence of download attribute
+    if (document.activeElement && document.activeElement.hasAttribute('download')) {
+      return;
+    }
     this.JSONRPC.notification('unload');
     this.trigger('xfc.unload');
   }