rem: return false; 
add: return -1; 
context:   indexOf: function(object) {    for (var i = 0; i < this.length; i++)      if (this[i] == object) return i;    return false;  },
meta: 5150	/local1/tlutelli/issta_data/temp/all_js/javascript/2006_temp/2006/5150/44d85be227cc8496144d82df38b82dfcc1224861/prototype.js/clean/intermine/webapp/main/resources/main/js/prototype.js