anchor.diff:          browser.SwitchTo().Alert().Dismiss()
           true)
       
  +(* what is box? *)
  +module Jw = 
  +    open System
  +    let _byte = 'c'B
  +    let _byteToObject = box _byte
  +    let _objectToByte = unbox<byte> _byteToObject
  +
  +    let _date = new DateTime(2015,10,10)
  +
  +    let _dateToObject = box _date
  +    let _objectToDate = unbox<DateTime>  _dateToObject
  +    ()
  +
   //assertions    
   let ( == ) item value =
       match box item with
  
positive.code: [<AutoOpen>]
  module canopy.core
  
  
negative.code:             var classes = [];
              var all = document.getElementsByTagName('*');
              for (var i=0, max=all.length; i < max; i++) {
                  var ary = all[i].className.split(' ');
                  for(var j in ary){
                      if(ary[j] === ''){
                          ary.splice(j,1);
                          j--;
                      }
                  }
                 classes = classes.concat(ary);
              }
              return classes;"""
  