jQuery to limit number of checkboxes checked by User

Introduction:

Many time we need to limit the selection of checkboxes users can select or in other words users are not allowed to select more than a number of checkbox to give their choice. For example, out of all client side script language, user can select maximum three where he is best.

As for example, take a look at below HTML checkboxlist

HTML:

 jQuery 

JavaScript 

 Prototype

 Dojo

 Mootools 

JS:

$(document).ready(function () {
   $("input[name='tech']").change(function () {
      var maxAllowed = 2;
      var cnt = $("input[name='tech']:checked").length;
      if (cnt > maxAllowed) 
      {
         $(this).prop("checked", "");
         alert('Select maximum ' + maxAllowed + ' technologies!');
     }
  });
});