Start workflow SharePoint 2013 programmatically

Javascript :)  

   // ---------- Start workflow ---------- 
    function StartWorkflow() { 
      var errorMessage = "An error occured when starting the workflow."; 
      var subscriptionId = "", itemId = "", redirectUrl = ""; 
 
      var urlParams = GetUrlParams(); 
      if (urlParams) { 
        //itemGuid = urlParams["ItemGuid"]; 
        itemId = urlParams["ID"]; 
        redirectUrl = urlParams["Source"]; 
        subscriptionId = urlParams["TemplateID"]; 
      } 
 
      if (subscriptionId == null || subscriptionId == "") { 
        // Cannot load the workflow subscription without a subscriptionId, so workflow cannot be started. 
        alert(errorMessage + "  Could not find the workflow subscription id."); 
        RedirFromInitForm(redirectUrl); 
      } 
      else { 
        // Set workflow in-arguments/initiation parameters 
        var wfParams = new Object(); 
 
        // get reviewer loginname 
        var html = $("#ctl00_PlaceHolderMain_docReviewerUser_upLevelDiv"); 
        wfParams['DocReviewerLoginName'] = $("#divEntityData", html).attr("key"); 
        // get editor loginname 
        var html = $("#ctl00_PlaceHolderMain_docEditorUser_upLevelDiv"); 
        wfParams['DocEditorLoginName'] = $("#divEntityData", html).attr("key"); 
 
        // Get workflow subscription and then start the workflow 
        var context = SP.ClientContext.get_current(); 
        var wfManager = SP.WorkflowServices.WorkflowServicesManager.newObject(context, context.get_web()); 
        var wfDeployService = wfManager.getWorkflowDeploymentService(); 
        var subscriptionService = wfManager.getWorkflowSubscriptionService(); 
 
        context.load(subscriptionService); 
        context.executeQueryAsync( 
 
            function (sender, args) { // Success 
              var subscription = null; 
              // Load the workflow subscription 
              if (subscriptionId) 
                subscription = subscriptionService.getSubscription(subscriptionId); 
              if (subscription) { 
                if (itemId != null && itemId != "") { 
                  // Start list workflow 
                  wfManager.getWorkflowInstanceService().startWorkflowOnListItem(subscription, itemId, wfParams); 
                } 
                else { 
                  // Start site workflow 
                  wfManager.getWorkflowInstanceService().startWorkflow(subscription, wfParams); 
                } 
                context.executeQueryAsync( 
                    function (sender, args) { 
                      // Success 
                      RedirFromInitForm(redirectUrl); 
                    }, 
                    function (sender, args) { 
                      // Error 
                      alert(errorMessage + "  " + args.get_message()); 
                      RedirFromInitForm(redirectUrl); 
                    } 
                ) 
              } 
              else { 
                // Failed to load the workflow subscription, so workflow cannot be started. 
                alert(errorMessage + "  Could not load the workflow subscription."); 
                RedirFromInitForm(redirectUrl); 
              } 
            }, 
            function (sender, args) { // Error 
              alert(errorMessage + "  " + args.get_message()); 
              RedirFromInitForm(redirectUrl); 
            } 
        ) 
      } 
    } 
 
    // ---------- Redirect from page ---------- 
    function RedirFromInitForm(redirectUrl) { 
      window.location = redirectUrl; 
    } 
 
    // ---------- Returns an associative array (object) of URL params ---------- 
    function GetUrlParams() { 
      var urlParams = null; 
      if (urlParams == null) { 
        urlParams = {}; 
        var parts = window.location.href.replace(/[?&]+([^=&]+)=([^&]*)/gi, function (m, key, value) { 
          urlParams[key] = decodeURIComponent(value); 
        }); 
      } 
      return urlParams; 
    } 

C#

var WSM = new WorkflowServicesManager(web);
var wfSubscriptionService = WSM .GetWorkflowSubscriptionService();
//get all workflows associated with the list
var subscriptions =  wfSubscriptionService .EnumerateSubscriptionsByList(listId);
//run all workflows associated with the list
foreach (var workflowSubscription in subscriptions)
{    
   //initiation parameters    
   var inputParameters = new Dictionary();    
   inputParameters.Add("WFProperty", "Value"); 
   WSM .GetWorkflowInstanceService().StartWorkflowOnListItem(workflowSubscription, itemId, inputParameters);
}

Start: Set up and configure SharePoint 2013 Workflow Manager

Reference :

http://code.msdn.microsoft.com/office/SharePoint-2013-Approval-f5ac5eb2