Set TaskOutcome using JavaScript

Question

I created custom task display form and need to add 2 buttons to allow user approve and reject task in display mode. How can I set TaskOutcome value using JS?

My code is the following:

<td class="ms-toolbar" nowrap="nowrap" align="right">
<input id="buttonaccept" type="button" value="Утвердить" onclick="javascript:  somehow set the TaskOutcome value; {ddwrt:GenFireServerEvent('__commit;')}" />
</td>

Thanks

Answer 1

If anyone will have the same question - you can do this via client object model supported by Microsoft. Here is a pice of code, which will help you:

  var QueryString = function () {
      // This function is anonymous, is executed immediately and 
      // the return value is assigned to QueryString!
      var query_string = {};
      var query = window.location.search.substring(1);
      var vars = query.split("&");
      for (var i=0;i<vars.length;i++) {
        var pair = vars[i].split("=");
         // If first entry with this name
        if (typeof query_string[pair[0]] === "undefined") {
          query_string[pair[0]] = pair[1];
         // If second entry with this name
        } else if (typeof query_string[pair[0]] === "string") {
          var arr = [ query_string[pair[0]], pair[1] ];
          query_string[pair[0]] = arr;
         // If third or later entry with this name
        } else {
          query_string[pair[0]].push(pair[1]);
        }
      } 
        return query_string;
    } ();

    function onQuerySucceeded() {

        //alert('Item updated!');
    }

    function onQueryFailed(sender, args) {

        alert('Request failed. ' + args.get_message() + '\n' + args.get_stackTrace());
    }

    function updateItem(taskoutcome) {
       var clientContext = new SP.ClientContext.get_current();
       var oList = clientContext.get_web().get_lists().getByTitle('Задачи');
       this.oListItem = oList.getItemById(QueryString.ID);
       oListItem.set_item('TaskOutcome', taskoutcome);
       oListItem.set_item('Status', 'Завершена');

      var bodycontent = document.getElementById('bodytdid').innerHTML;
      oListItem.set_item('Body', bodycontent);

       oListItem.update();              
       clientContext.executeQueryAsync(Function.createDelegate(this, this.onQuerySucceeded), Function.createDelegate(this, this.onQueryFailed));
    }

More details can found in http://vh4u.blogspot.ru/2013/03/sharepoint-2013-approve-and-reject.html