<script>
var radioinput = '';
function setVal(v) {
radioinput = v;
}
</script>
<input type="radio" onclick="setVal(this.value)" value="1" name="c">
<input type="radio" onclick="setVal(this.value)" value="2" name="c">
....
<input onclick="JXP(1, 'secili', 'siparis.php','list=1&c='+radioinput);" value=" Gonder " type="button" name="button">