var xmlhttp = false;

function processChange() {
  if (xmlhttp.readyState == 4 && xmlhttp.status==200) { 
	var json = !(/[^,:{}\[\]0-9.\-+Eaeflnr-u \n\r\t]/.test(xmlhttp.responseText.replace(/"(\\.|[^"\\])*"/g, ''))) &&  eval('(' + xmlhttp.responseText + ')'); 
	var  cenadopravy = document.getElementById("cenadopravy");
	var  cenaspostovnym = document.getElementById("cenaspostovnym");
	cenadopravy.innerHTML = json.cenadopravy;
	cenaspostovnym.innerHTML = json.cenaspostovnym;
  }
}
function CheckField() {
	if (window.XMLHttpRequest)
	  {// code for IE7+, Firefox, Chrome, Opera, Safari
		xmlhttp=new XMLHttpRequest();
	  }
	else
	  {// code for IE6, IE5
		xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
	  }
	
  xmlhttp.onreadystatechange = processChange;
  var doprava = document.getElementById("doprava");
  var platba = RadioCheck();
  var parameters="platba="+platba+"&dopravce="+doprava.value; 
  xmlhttp.open("POST", "/vypoctidopravujson.php", true);
  xmlhttp.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
  xmlhttp.send(parameters);
}


function RadioCheck() {
var selection = document.objednatform.platba;

for (i=0; i<selection.length; i++)

  if (selection[i].checked == true)
  {
	  var hodnota=selection[i].value;
  }
return hodnota;
}