text: /*
  Description:
  Implement String#to_cents, which should parse prices expressed as $1.23 and return number of cents, or in case of bad format return nil.
  */
  String.prototype.toCents=function(){
    if (/^\$\d+\.\d{2}$/.test(this)) return this.replace(/[^0-9]/g,'')*1
    return null
  }
  