Fix #1758: Correct bootstrap module parser

CHANGE.md

@@ -5,6 +5,7 @@ Change Log: `bootstrap-fileinput`
 
 **Date**: _under development_
 
+- (bug #1758): Correct bootstrap module parser.
 - (enh #1756): Replace `getLoadingUrl` to a new `$h.getZoomPlaceholder` method.
 
 ## version 5.2.5

js/fileinput.js

@@ -24,8 +24,8 @@
     $.fn.fileinputThemes = {};
 
     if (!$.fn.fileinputBsVersion) {
-        var v = (bootstrap && bootstrap.Alert && bootstrap.Alert.VERSION) || (Alert && Alert.VERSION) || '3.x.x';
-        $.fn.fileinputBsVersion = v;
+        $.fn.fileinputBsVersion = (window.bootstrap && window.bootstrap.Alert && window.bootstrap.Alert.VERSION) ||
+            (window.Alert && window.Alert.VERSION) || '3.x.x';
     }
 
     String.prototype.setTokens = function (replacePairs) {