rem: return value != undefined || value != null; 
add: return value != null; 
context:     return this.select(function(value) {      return value != undefined || value != null;    });
meta: 1371	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/1371/53dfa93e53bccf5af1729cbdce88cb70e1ffcca5/prototype.js/clean/public/javascripts/prototype.js