For example. You got 1 list with 3 options.
a
b
c
once someone select a
it instantly appears a text through php under the list or above it.
Without to reload or anything else. I have seen it before 100%.
pseudo code
<li>
<option 1> a</o>
<option 2> b</o>
<option 3> c</o>
</li>
<?php
if(option 1 is selected)
{
echo "YEAH B1tch";
}
else if(option 2 is selected)
{
echo "NO Sh1TZ";
}
else if(option 3 is selected)
{
echo "DaMn uR rIgHt";
}