My list is:

<select name="sel_audio" id="sel_audio">
    <option value="endo/audio/beep.wav" selected="selected">beep </option>
    <option value="endo/audio/dig1.wav">dig1 </option>
    <option value="endo/audio/IMAlert.wav">IMAlert </option>
    <option value="endo/audio/IMAlertDef.wav">IMAlertDef </option>
</select>

I want ot add HighPiono.wav file to list. My code is:

self.script = "document.getElementById('sel_audio').value='" + C:musicHighPiono.wav + "';"
driver.execute_script(self.script)

This code is setting the blank value  in list without giving any error.

Please help me.