title: compute age from given birthdate
body: <p>I have 2 comboboxes and 2 textboxes. My first combobox contains months in this format january, february, etc, and the other combobox contains numbers from 1 to 31. My first textbox is <code>txtyear</code>. Once the user input birth year to <code>txtyear</code> a variable <code>BOD</code> will be equals to this. </p>
  
  <pre><code>Dim BOD as string
  BOD = cbomonth.text + "-" + cboday.text + "-" + txtyear.text
  </code></pre>
  
  <p>The purpose of my last textbox is to handle the age of the user that will be computed when the cursor lost focus on <code>txtyear</code>.</p>
  
  <p>Can anyone help how to compute the age.</p>