// JavaScript Document
    function kontrola_rezervace(){
    var jmeno=document.getElementById("jmeno").value;
    var mobil=document.getElementById("mobil").value;
    var email=document.getElementById("email").value;
         
      if((email=="")||(email.indexOf("@")==-1)||(email.indexOf(".")==-1)||(jmeno=="")||(mobil=="")){
     window.alert("Musíte zadat povinné položky!\n");
      return false;
     }
     else{
     return true;
     }
    }
    
    
    function kontrola_rezervace_en(){
    var jmeno=document.getElementById("jmeno").value;
    var mobil=document.getElementById("mobil").value;
    var email=document.getElementById("email").value;
         
      if((email=="")||(email.indexOf("@")==-1)||(email.indexOf(".")==-1)||(jmeno=="")||(mobil=="")){
     window.alert("You must enter the required items!\n");
      return false;
     }
     else{
     return true;
     }
    }
    
    function kontrola_rezervace_de(){
    var jmeno=document.getElementById("jmeno").value;
    var mobil=document.getElementById("mobil").value;
    var email=document.getElementById("email").value;
         
      if((email=="")||(email.indexOf("@")==-1)||(email.indexOf(".")==-1)||(jmeno=="")||(mobil=="")){
     window.alert("Sie müssen die obligatorischen Artikel füllen!\n");
      return false;
     }
     else{
     return true;
     }
    }