title: Bootstrap Tour : dont move to next step if current step input filed is empty
body: <p>In the bootstrap walkthrough we have next and prev buttons.
  In this on click next button we move to next step.</p>
  
  <p>But I want to add condition in that If that input filed is empty then walkthrough should not move to next it should stay on current step only.</p>
  
  <p>Following is reference code: </p>
  
  <pre><code>rec = {
          aa: responseData[i].fields.aa,
          bb: responseData[i].fields.bb,                  
          cc: responseData[i].fields.cc,
          element: responseData[i].fields.element_selector,
          placement: responseData[i].fields.modal_placement,      
          title: responseData[i].fields.modal_title,
          content: responseData[i].fields.modal_content,
          onShow: show_fn,        
          onNext : function () {  
                      var dir = 'next';
                      this_selector = this.element;
                      this_selected_elem = $(this_selector).find('option:selected').val();                                     
                      console.log(this_selected_elem); 
                      if(this_selected_elem == ''){
                          console.log('--prev---');                                                                                
                      }                               
                  }   
      }
  </code></pre>
  
  <p>//rec is pushing in allRec array.</p>
  
  <pre><code>aps.workFlow.allRec.push(rec);
  
  
  
  for(var i = 0 ; i&lt; aps.workFlow.allRec.length; i++){
      if (aps.workFlow.allRec[i].aa == walkthroughType){
          element_selector = aps.workFlow.allRec[i].element;
          selected_elem = $(element_selector).find('option:selected').val();
          open_elem = aps.workFlow.allRec[i].onShow;  
          if(selected_elem == undefined || selected_elem == ''){              
              aps.workFlow.allRec1.push(aps.workFlow.allRec[i]);//Adding records in allRec1 array which is going to pass as walkthrough steps.                            
          }                                           
      }   
  }
  aps.walk.setupBootstrap();  // this is the function which is having tour steps setup.
  
  
  
  aps.walk = {
      setupBootstrap : function(){    
          //dir = 'next';
          tour = new Tour();  
          tour.end(); 
          //tour.addSteps(aps.workFlow.arrayRec1);    
          console.log('-----aps.workFlow.allRec1-------------')
          console.log(aps.workFlow.allRec1)
          tour.addSteps(aps.workFlow.allRec1);    
          tour.init();    
          tour.start();
  
          if (tour.ended()) { 
              $('&lt;div class="alert alert-info alert-dismissable"&gt;&lt;button class="close" data-dismiss="alert" aria-hidden="true"&gt;&amp;times;&lt;/button&gt;You ended the demo tour. &lt;a href="#" data-demo&gt;Restart the demo tour.&lt;/a&gt;&lt;/div&gt;').prependTo(".content").alert();
              tour.restart(); 
          }   
  
          $(document).on("click","#proposal_command_list #create_tour", function(e) {
              e.preventDefault();
              if ($(this).hasClass("disabled")) {
                  return;
              }           
              //tour._options.steps = aps.workFlow.arrayRec1      
              tour._options.steps = aps.workFlow.allRec1      
              return $(".alert").alert("close");          
          }); 
          //tour.restart();
      }
  }
  </code></pre>