Merge pull request #259 from beksultan28/patch-1

Update 03-cross-window-communication/article.md

Author: iliakan

4-frames-and-windows/03-cross-window-communication/article.md

@@ -27,7 +27,7 @@ If we have a reference to another window (a popup or iframe), and that window co
 
 If it comes from another origin, then we can only change its location. Please note: not *read* the location, but *modify* it, redirect it to another place. That's safe, because the URL may contain sensitive parameters, so reading it from another origin is prohibited, but changing is not.
 
-Also such windows windows may exchange messages. Soon about that later.
+Also such windows may exchange messages. Soon about that later.
 
 ````warn header="Exclusion: subdomains may be same-origin"