SLameN, за то, что хоть тестовый пример сделал...
Как вариант.
<!DOCTYPE html>
<html>
<head>
<meta http-equiv='Content-Type' content='text/html; charset=windows-1251' />
<!--
<script src='http://code.jquery.com/jquery-latest.js'></script>
<script src="https://code.angularjs.org/1.3.9/angular.min.js"></script>
<script src="https://code.angularjs.org/1.3.9/angular-route.js"></script>
<link rel='stylesheet type=text/css href=tmp.css' />
<link rel="stylesheet/less" type="text/css" href="style.less">
<script src="http://cdnjs.cloudflare.com/ajax/libs/less.js/2.5.0/less.min.js"></script>
-->
<style type='text/css'>
</style>
<script type='text/javascript'>
function test(Obj){
var val=(Obj.value=='')? '': Obj.id;
document.getElementById('idData'+Obj.id).value=val;
};
</script>
</head>
<body>
<input type='text' name='idData1' id='idData1' />
<input type='text' name='idData2' id='idData2' />
<select name='countData[]' id='1' onchange="test(this)">
<option></option>
<option>1</option>
<option>2</option>
</select>
<select name='countData[]' id='2' onchange="test(this)">
<option></option>
<option>1</option>
<option>2</option>
</select>
</body>
</html>