#378 Optimize and refactor JQuery

Create variables for jQuery objects instead of searching the DOM tree over and over again for the same DOM Element.
Get objects by classname from subtree elements selected by ID instead from root Document.
http://api.jquery.com/data/#data-html5

Every attempt is made to convert the string to a JavaScript value (this includes booleans, numbers, objects, arrays, and null) otherwise it is left as a string. To retrieve the value's attribute as a string without any attempt to convert it, use the attr() method.