Include this in your html head
<script src="http://code.jquery.com/jquery-latest.min.js"></script>
Assuming your HTML looks like this:
<select name="products" id="products">
<option value="phone">Phone</option>
<option value="laptop">Laptop</option>
<option value="shirt">Shirt</option>
</select>
<input type="submit" id="submit"/>
<div id="selection"></div>
Use jquery to get the value on click event of submit and write that value in selection div:
<script>
$('#submit').click(function(e){
var selected=$("#products option:selected").val();
$('#selection').append("<p>"+selected+"</p>");
e.preventDefault();
});
</script>