title: Error undefined is not a function for .click()
body: <p>I keep getting <code>undefined is not a function</code> error and I don't know why, can anyone help shed some light.</p>
  
  <p>here is the whole bit of code</p>
  
  <pre><code> (function(){
  
                  var sliders = $('section.content-25').hide();
                  var slidersOrder = sliders.each(function(i){
                                                  var i = i - 1;
                                                  $(this).addClass("slider"+(i+1));
                                              });
  
                  $(".project-wrapper").on('click', function(){
  
                      var btnOrder = $(this).index();
                      var sliderClass = ("slider"+btnOrder);
  
                       if (sliders.hasClass("slider"+btnOrder)) {
  
                              sliderClass.show();
  
                       }; 
                      event.preventDefault();
  
                   });//end of .on('click') function
  
              })();// end self envoking functions
  </code></pre>