title: add day to date javascript
body: <p>I want to add a day to date I get from textbox.I tried the code below but it did not work</p>
  
  <pre><code>    function get_renew_date ()
      {
          var chkautorenew=document.getElementById("MainContent_chk_Isauto_Renew");
          if (chkautorenew.checked) {
              end_date = document.getElementById("MainContent_txtContract_End_date").value;
              renew_date = document.getElementById("MainContent_txtContract_Renew").value;
              dat = new Date(end_date.toDateString());
              //renew_date=dat.addDays(1);
              alert(end_date.toDateString());
          }
       }
  </code></pre>
  
  <p>I'm also worried about the client date format and the last day of the month, how can I be sure that after adding a day it will not be like this 32/03/2016</p>
  
  <p>thank you</p>