Full working solution :
HTML:
<form id="myform">
<button>erase</button>
<select id="fs">
<option value="Arial">Arial</option>
<option value="Verdana ">Verdana </option>
<option value="Impact ">Impact </option>
<option value="Comic Sans MS">Comic Sans MS</option>
</select>
<select id="size">
<option value="7">7</option>
<option value="10">10</option>
<option value="20">20</option>
<option value="30">30</option>
</select>
</form>
<br/>
<textarea class="changeMe">Text into textarea</textarea>
<div id="container" class="changeMe">
<div id="float">
<p>
Text into container
</p>
</div>
</div>
jQuery:
$("#fs").change(function() {
//alert($(this).val());
$('.changeMe').css("font-family", $(this).val());
});
$("#size").change(function() {
$('.changeMe').css("font-size", $(this).val() + "px");
});
Fiddle here: http://jsfiddle.net/AaT9b/