diff --git a/book/some_content/HTML_elements.md b/book/some_content/HTML_elements.md
index 9e659b3..d591355 100644
--- a/book/some_content/HTML_elements.md
+++ b/book/some_content/HTML_elements.md
@@ -6,4 +6,4 @@ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor i
 
 Now create another one where we try percentages
 
-<iframe src="../_static/pdf_and_cdf.html" width="100%" height="50vw" frameborder="0"></iframe>
+<iframe src="../_static/pdf_and_cdf.html" width="100%" height="100%" frameborder="0"></iframe>