JQuery implements statistics on the number of checkboxes selected

The code is very brief, the function is also very simple, but very practical, here is not detailed directly on the code

JQuery code:

        function countNum(){ 

          //alert($('input[name=check]:checked').length); 

         var arrays = new Array(); 

          var items = document.getElementsByName("check"); 

          for(var i=0;i<items.length;i++){ 

              if(items[i].checked){ 

                  arrays.push(items[i].value); 

              } 

          } 

          alert(arrays.length); 

        }

HTML code:

    <input type="checkbox" value="1" name="check" checked/> 

    <input type="checkbox" value="2" name="check"/> 

    <input type="checkbox" value="3" name="check"/> 

    <input type="button" value=" Select the number of " id="btn" onclick="countNum();"> 

If you have the same requirements in the project, please refer to it. If you have a better way, please contact me.