add: this.mPreviewButton = document.getElementById("preview"); 
context:   init: function()  {    this.soundUrlLocation = document.getElementById("soundUrlLocation");    this.newMailNotificationType = document.getElementById("newMailNotificationType");    this.systemSoundCheck();  },
meta: 5872	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5872/ef422a10ed2c174ae4f57fe26d40ade17e24162d/notifications.js/clean/mail/components/preferences/notifications.js