Enable/disable beeps.
[read/write property] enableBeeps([out, retval] VARIANT_BOOL *on) enableBeeps([in] VARIANT_BOOL on)
Normally, XpdfViewer will emit a beep on various error conditions (attempting to go to the previous page from page one, attempting to go to the next page from the last page, a text find string that isn't found, etc.). This property enables or disables beeps. The default value is enabled.
viewer.enableBeeps = False