This isnt really a php issue. The data the php recieves at the other end should be the same regardless of how the information is captured.
Obviously this assumes you have a span or other container with an id of 'search' to put the search box into and that statedropdown, yesno and standardtextinput have already been set as the html that you want to use
//onChange for field dropdown
field = document.getElementById('ctlSearchField');
document.getElementById('search').innerHTML = statedropdown;
case "Surrendered A Pug Before? (Yes/No)":
document.getElementById('search').innerHTML = yesno;
document.getElementById('search').innerHTML = standardtextinput;