diff --git a/web/web/viewer.css b/web/web/viewer.css
index 809666a..0a1ff8a 100644
--- a/web/web/viewer.css
+++ b/web/web/viewer.css
@@ -232,6 +232,10 @@
   background-clip: content-box;
   border-image: url(images/shadow.png) 9 9 repeat;
   background-color: white;
+  -webkit-user-select: none;
+  -moz-user-select: none;
+  -ms-user-select: none;
+  user-select: none;  
 }
 
 .pdfViewer.removePageBorders .page {