there is good trick to hide/display div or another content with checkboxes/radio inputs and pure css like in example bellow.

.theTrick {display:none;}
#display_yes:checked ~ .theTrick {display: block;}

<input type="radio" id="display_yes" name="display" value="somethin">
<label for="display_yes">YES</label>

<input type="radio" id="display_no" name="display" value="somethin">
<label for="display_no">NO</label>

<div class="theTrick">Hello world!</div>

https://jsfiddle.net/dz1vLxqu/

Its pretty cool and without external scripts. Is there solution for to do this with dropdown list instead of checkboxes?

<select>
<option> 
...