// JavaScript Document
/*** zakladni funkce ***/

function objGet(x) {
	if (typeof x != 'string') return x;
	else if (Boolean(document.getElementById)) return document.getElementById(x);
	else if (Boolean(document.all)) return eval('document.all.'+x);  // pro MSIE 4
	else return null;
}

function objSetStyle (obj,prop,val) {
	var o = objGet(obj);
	if (o && o.style) {
		eval ('o.style.'+prop+'="'+val+'"');
		return true;
	}
	else return false;
}

function objShow (obj,on) {
	return objSetStyle(obj,'visibility',(on) ? 'visible':'hidden');
}

function objDisplay (obj,on,type) {
	if (on && !type) type = 'block';
	return objSetStyle(obj,'display',(on) ? type:'none');
}

// vrati vybrany (oznaceny) text na strance
// http://www.quirksmode.org/js/selected.html
function getSel(el) {
   var selection = false;
   var begin,selection,end;
   if (navigator.userAgent.toLowerCase().indexOf("firefox") > 0) {
      // firefox
      if (el.selectionStart!= undefined) {
         begin = el.value.substr(0, el.selectionStart);
         selection = el.value.substr(el.selectionStart, el.selectionEnd - el.selectionStart);
         end = el.value.substr(el.selectionEnd);
      }
   } else { 
      // other
      if (window.getselection){
         selection = window.getselection();
      } else if (document.selection) {
         selection = document.selection.createRange().text;
      } else if (document.getSelection) {
         selection = document.getSelection();
      }
   }
   return selection;
}

// incrementuje / decrementuje hodnotu ve vstupnim poli
function InputIncrem(inp_id) {
   AheadNum = parseInt(objGet(inp_id).value);
   objGet(inp_id).value = AheadNum + 1;
}
function InputDecrem(inp_id) {
   AheadNum = parseInt(objGet(inp_id).value);
   if(AheadNum > 0) {
      objGet(inp_id).value = AheadNum - 1;
   }
}

// Funkce na potvrzení akce
function potvrzeni(dotaz) {
   if (!dotaz) var dotaz = "Jste si jisti?";
   if (!confirm(dotaz)) return false;
   return true;
}
function tisk() {
    if (confirm("Vytisknout tuto stránku?")) {
      window.print();
    }
}

// Forumlare
//** zjistni hodnoty zvoleneho radiobutonu
function get_form_radio_selected(testform, inputname) {
   eval("var testinput = document."+ testform +"."+ inputname +";");
   if (!testinput) {
      return false;
   }
   if (testinput.value) {
      return testinput.value;
   }
   for (i=0; i < testinput.length; i++) {
      if (testinput[i].checked) {
         return testinput[i].value;
      }
   }
   return false;
}

//** test zatrzeni alespon 1 CHECKBOXu (NEPOUZITO)
function check_form_checkbox_checked(testform, testinput) {
   eval("var form_length = testform.elements.length;");
   for (var i=0; i < form_length; i++) {
      var element = testform.elements[i];
      if (element.name == testinput) {
         if (element.checked)
            return true;
      }
   }
   return false;
}

//** zaskrtnuti CHECKBOXu (NEPOUZITO)
function checkbox_change(form_name, check_name, array_num) {
   eval("var form = document."+ form_name +";");
   if (!form) {
      return false;
   }
   eval("var form_length = document."+ form_name +".elements.length;");
   var j = 0;
   for (var i=0; i < form_length; i++) {
      var element = form.elements[i];
      if (element.name == check_name) {
         if (j == array_num) {
            element.checked = (element.checked)? false : true;
            return true;
         } else {
            j++;
         }
      }
   }
}