return this + 1; 
return this.slice(0, this.length - 1) + String.fromCharCode(this.charCodeAt(this.length - 1) + 1); 
  succ: function() {    return this + 1;  },
742	/local1/tlutelli/issta_data/temp/all_js/javascript/2007_temp/2007/742/53dfa93e53bccf5af1729cbdce88cb70e1ffcca5/prototype.js/clean/public/javascripts/prototype.js