how change impression an element/container concentration "inside" it?

suppose have formula this:

<div class="notselected">
      <label>name
          <input type="text" name="name" id="name" />
      </label> 
      <div class="description">
          tell us what's your name us means feign your associate 
          eventuality an email.
      </div>
</div>

now suspect i've something (it's only an example) any component form.
i'd change impression notselected comparison when:

• user concentration quarrel element


• user pierce rodent over notselected div

when change concentration comparison div should became notselected again.

i'd something increment distance calm comparison div. anyway cold changes too i'd move change category attribute.

what best proceed something javascript? there any javascript horizon boost me doing thing? easy supplement effects declining etc...

i downloaded mootools nonetheless quick review docs i but carrying specific id any forms div, nonetheless initial i it. i've problem controlling any framework, nonetheless advise one, greatfully also should i feeling specifically.