title: javascript add month to date
body: <p>I want to add 1 Month or 6 Month to a given Date.
  But if i add one Month, the year isnt incremented. And if i add 6 Month to June, i got the Month 00 returned BUT the year is incremented.
  Could you please help me out?</p>
  
  <pre><code>function addToBis(monthToAdd){
          var tmp = $("#terminbis").val().split('.');
  
          var day = tmp[0];
          var month = tmp[1];
          var year = tmp[2];
  
          var terminDate = new Date(parseInt(year),parseInt(month), parseInt(day));
          terminDate.setMonth(terminDate.getMonth()+monthToAdd);
  
          day = "";
          month = "";
          year = "";
  
          if(terminDate.getDate() &lt; 10){
              day = "0"+terminDate.getDate();
          } else{
              day = terminDate.getDate();
          }
  
          if(terminDate.getMonth() &lt; 10){
              month = "0"+terminDate.getMonth();
          } else{
              month = terminDate.getMonth();
          }
  
          year = terminDate.getFullYear();
  
  
          $("#terminbis").val(day+"."+month+"."+year);
      }
  </code></pre>