add: return "dummy"; 
context:     function negate_comparison_type(type) {        switch(type) {            case "substring": return "notsubstring";            case "anywords":  return "nowords";            case "regexp":    return "notregexp";            default:                // e.g. "greaterthan"                 alert("Can't negate comparison type: `" + type + "'");                abort = true;        }    }
meta: 9421	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/9421/54b8850bf6335ea6b3f6eba92a689316ac27d3cd/quicksearch.js/buggy/webtools/bugzilla/quicksearch.js