Update file_input.py
This example is using `js_on_change` to respond to an internal "change" event instead of a specific property. I don't believe this has ever been officially endorsed and AFAIK this is not demonstrated any place else. Updating to respond to the `filename` property.
@@ -12,8 +12,7 @@ callback = CustomJS(args=dict(para=para, file_input=file_input), code="""
""")
# Attach callback to FileInput widget
-file_input.js_on_change('change', callback)
-
+file_input.js_on_change('filename', callback)
output_file("file_input.html")
