DOC: Add JavaScript example

docs/index.rst

@@ -32,9 +32,10 @@ You can contribute to `pypdf on GitHub <https:/py-pdf/pypdf>`_.
  user/encryption-decryption
  user/merging-pdfs
  user/cropping-and-transforming
- user/add-watermark
  user/reading-pdf-annotations
  user/adding-pdf-annotations
+ user/add-watermark
+ user/add-javascript
  user/viewer-preferences
  user/forms
  user/streaming-data

docs/user/add-javascript.md

@@ -0,0 +1,21 @@
+# Adding JavaScript to a PDF
+
+PDF readers vary in the extent they support JavaScript, with some not supporting it at all.
+
+Adobe has documentation on its support here:
+https://opensource.adobe.com/dc-acrobat-sdk-docs/library/jsapiref/index.html
+
+## Launch print window on opening
+
+```python
+from pypdf import PdfWriter
+
+writer = PdfWriter(clone_from="example.pdf")
+
+# Add JavaScript to launch the print window on opening this PDF.
+writer.add_js("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")
+
+# Write to pypdf-output.pdf.
+with open("pypdf-output.pdf", "wb") as fp:
+ writer.write(fp)
+```

docs/user/cropping-and-transforming.md

@@ -24,12 +24,6 @@ page3.mediabox.upper_right = (
 )
 writer.add_page(page3)
 
-# Add some JavaScript to launch the print window on opening this PDF.
-# The password dialog may prevent the print dialog from being shown,
-# comment the encryption lines, if that's the case, to try this out.
-# https://opensource.adobe.com/dc-acrobat-sdk-docs/library/jsapiref/index.html
-writer.add_js("this.print({bUI:true,bSilent:false,bShrinkToFit:true});")
-
 # Write to pypdf-output.pdf.
 with open("pypdf-output.pdf", "wb") as fp:
  writer.write(fp)