rem:  document.getElementById("preview").disabled = (document.getElementById("finishedSoundUrl").value == ""); 
context: function Browse(){  var fp = Components.classes["@mozilla.org/filepicker;1"]                     .createInstance(nsIFilePicker);  // XXX todo, persist the last sound directory and pass it in  // XXX todo filter by .wav  fp.init(window, document.getElementById("browse").getAttribute("filepickertitle"), nsIFilePicker.modeOpen);  fp.appendFilters(nsIFilePicker.filterAll);  var ret = fp.show();  if (ret == nsIFilePicker.returnOK) {    var soundUrl = document.getElementById("finishedSoundUrl");    // convert the nsILocalFile into a nsIFile url     soundUrl.value = fp.fileURL.spec;  }  document.getElementById("preview").disabled =    (document.getElementById("finishedSoundUrl").value == "");}
meta: 10234	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/10234/f6bc7bcc0efd8fbaf5a1f1e049624f306272829a/pref-download.js/clean/xpfe/components/prefwindow/resources/content/pref-download.js