title: Merge a cell in excel, depending on it's value
body: <p>I want to merge a cell automatically with the one underneath if the cell has a certain <code>value ("vv")</code>. 
  a solution i found is to check every cell in an array every time a change is made, but thought there would be a possibility to check the value of a <code>cell</code> after it <code>changed</code>? </p>
  
  <p>So if I enter in a blank cell <code>"vv"</code> (without quotes) and I select a different cell I'd like that cell (with vv in it) to merge with the one right under it. 
  in my solution with the array it takes a second every time you change a cell, which is not neat if you make a lot of changes. 
  Any help? </p>