Sounds in web browsers for Zabbix frontend have been tested in the following browser versions and no additional configuration was required:
For playing sounds in Zabbix in the user's profile "GUI Messaging" should be enabled for all trigger severities and in the GUI global notification pop-up window sounds also should be enabled.
Quick Time Player is required.
To play sounds in MSIE7 and MSIE8:
In Windows Media Player in Tools→Options tab "File Types" is available only if user is a member of groups "Power Users" or "Administrators", i.e. regular User do not have access to this tab and do not see it.
Additional thing - if IE do not have some *.wav file in the local cache directory (%userprofile%\Local Settings\Temporary Internet Files) then sound will not play the first time.
For playing wav files in the Firefox browser can use one of the following applications: Windows Media Player or Quick Time plug-in. These configuration settings should be performed in the Tools→Options→Applications menu, there are settings for the "Wave sound (audio/wav)" -you should set Windows Media Player for playing these files.
Browsers where the sound did not work: