Javascript for calculating age

Javascript for calculating age

<script type="text/javascript">
       function showAge() {
          
           var d = document.getElementById('<%= txtDateOfBirth.ClientID %>').value.split('/');
           var today = new Date();
           var bday = new Date(d[2], d[1], d[0]);
           var by = bday.getFullYear();
           var bm = bday.getMonth() - 1;
           var bd = bday.getDate();
           var age = 0; var dif = bday;
           while (dif <= today) {
               var dif = new Date(by + age, bm, bd);
               age++;
           }
           age += -2;
           document.getElementById("<%=txtCurrentAge.ClientID %>").value = age;
           alert('You are ' + age + ' years old')
       }
</script>

//On page load ..

this.txtDateOfBirth.Attributes.Add("OnBlur", "javascript:return  showAge();");