Basic Select/Input Combo box

combox.js

// Add a class of "combox" to a select element to activate

function clonePosition(elementToMove, elementToClone){
  var $elementToClone = $(elementToClone);
  var position = $elementToClone.position();
  var top = position.top;
  var left = position.left;
  var width = $elementToClone.width() - 40;

  $(elementToMove).css({"position": "absolute", "top": top, "left": left, "width": width});
}

$("select.combox").each(function(){
  var select = $(this);
  var name = select.attr("name");
  select.attr("name", null);

  select.after("<input type=text name="+name+">");
  var textInput = select.next("input");
  clonePosition(textInput, select);
  textInput.val(select.val());

  select.on("change", function(){
    textInput.val(select.val());
    textInput.focus();
  });
});