<!--
  function prevody_jednotek(){
    var pocet = self.document.forms.pocetPr.pocet.value;
    var typ = self.document.forms.pocetPr.typ.value;
    if(pocet != "" && typ != ""){
      pocet = ((pocet == 10)? 10 : ((pocet == 20) ? 20 : ((pocet == 30) ? 30 : ((pocet == 40) ? 40 : 50))));
      var prikl = new Array;
      switch(typ){
        case "delky":     prikl = prevodDelky(pocet);
                          break;
        case "plochy":    prikl = prevodPlochy(pocet); 
                          break;
        case "objemu":    prikl = prevodObjemu(pocet);
                          break;
        case "hmotnosti": prikl = prevodHmotnosti(pocet);
                          break;                     
        case "delkyplochy": prikl = prevodDelkyPlochy(pocet);
                          break; 
        case "vse":       prikl = prevodDPO(pocet);
                          break;                                    
      }
             
      document.getElementById('priklady').innerHTML=vytvorFormPrikladuPyth(prikl, pocet);
    }
    
    return false;
  }
  
  
  function vytvorFormPrikladuPyth(prikl, pocet){
    var vyslform;
    vyslform = "<form action='' name='formPrikl' onSubmit='return vyhodnotPriklady()' method='post' class='' name='formPrikl' enctype='multipart/form-data'>"
                +"<fieldset>"
                  +"<legend>"+jazyk[0]+": "+pocet+"</legend>"
                    +"<table class='priklady'>";
                     

    var nahoda = Math.round(Math.random()*100);
    var ukazka;
    var datum = new Date();
    datum.setTime(datum.getTime() + 1 * 24 * 60 * 60 * 1000);
    var cookieExpires = "expires="+ datum.toGMTString()+";";
    document.cookie="nahoda="+nahoda+";"+ cookieExpires;
    id=0;
    for(i in prikl){
      ukazka = ""+prikl[i].prvni+" = "+prikl[i].druhy+" ";
      vyslform +=        "<tr><td></td>"
                              +"<td class='l'>"+prikl[i].prvni+" </td>"
                              +"<td class='l'> = <input type='text' name='priV' value='' maxlength='10' /> </td>"
                              +"<td class='l'>"+prikl[i].druhy+" "
                                +"<input type='hidden' name='priO' value='"+prikl[i].vysledek+"' />"
                                +"<input type='hidden' name='pri' value='"+ukazka+"' />"
                              +"</td>"
                              +"<td></td>"
                          +"</tr>";
      id++;
    }
  
    vyslform +=        "<tr><td></td>"
                            +"<td class='c' colspan='3'>"
                              +"<input type='hidden' name='pocet' value='"+pocet+"' />"
                              +"<input type='hidden' name='nahoda' value='"+nahoda+"' />"
                   					  +"<input type='submit' name='vysledkyOK' value='"+jazyk[1]+"' />"
                   		      +"</td>"
                            +"<td></td>"  
                        +"</tr>"
                      +"</table>"
                    +"</fieldset>"
                  +"</form>";
    return vyslform;
  } 

  /* objekt prikladu */
  function PrikladPorov(prvni, druhy, vysledek){
    this.prvni = prvni;
    this.druhy = druhy;
    this.vysledek = vysledek; 
  }
  
  function prevodDelky(pocet){
    var priklady = new Array;
    var citac = 0;
    var moc = 0;
    var delka = new Array('mm','cm','dm','m','km');
    var delky = new Array;
    delky['mm'] = "1";
    delky['cm'] = "10";
    delky['dm'] = "100";
    delky['m']= "1000";
    delky['km'] = "1000000";
    
    while(citac != pocet){
      if(moc++ > 5000){
        break;
      }
      var cis1 = Math.floor(((Math.random()*990)+10))/10;
      var zcis1 = Math.floor((Math.random()*delka.length));
      var zcis2 = Math.floor((Math.random()*delka.length));
      if(zcis1 == zcis2) continue;
      var znam1 = delka[zcis1];
      var znam2 = delka[zcis2];
      var rozdil = delky[znam1].length - delky[znam2].length;
      var nasobek = Math.pow(10,rozdil);
      var vysledek = Math.round(cis1*nasobek*1000000)/1000000; 
      
      
      if(!priklady[0]){
        priklady[0] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else if(!testShodyPrvADruh(priklady, cis1+" "+znam1, znam2)){
        priklady[citac] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else {
        continue;
      }
      citac++;
    }
    
    return priklady;
  }
  
  function prevodPlochy(pocet){
    var priklady = new Array;
    var citac = 0;
    var moc = 0;
    var delka = new Array('mm2','cm2','dm2','m2','a','ha','km2');
    var delky = new Array;
    delky['mm2'] = "1";
    delky['cm2'] = "100";
    delky['dm2'] = "10000";
    delky['m2']= "1000000";
    delky['a'] = "100000000";
    delky['ha'] = "10000000000";
    delky['km2'] = "1000000000000";
    
    while(citac != pocet){
      if(moc++ > 5000){
        break;
      }
      var cis1 = Math.floor(((Math.random()*990)+10))/10;
      var zcis1 = Math.floor((Math.random()*delka.length));
      var zcis2 = Math.floor((Math.random()*delka.length));
      if(zcis1 == zcis2) continue;
      var znam1 = delka[zcis1];
      var znam2 = delka[zcis2];
      var rozdil = delky[znam1].length - delky[znam2].length;
      if(Math.abs(rozdil)>6) continue;
      var nasobek = Math.pow(10,rozdil);
      var vysledek = Math.round(cis1*nasobek*1000000)/1000000; 
      
      
      if(!priklady[0]){
        priklady[0] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else if(!testShodyPrvADruh(priklady, cis1+" "+znam1, znam2)){
        priklady[citac] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else {
        continue;
      }
      citac++;
    }
    
    return priklady;
  }
  
  function prevodHmotnosti(pocet){
    var priklady = new Array;
    var citac = 0;
    var moc = 0;
    var delka = new Array('mg','g','kg','q','t');
    var delky = new Array;
    delky['mg'] = "1";
    delky['g'] = "1000";
    delky['kg'] = "1000000";
    delky['q'] = "100000000";
    delky['t'] = "1000000000";
    
    while(citac != pocet){
      if(moc++ > 5000){
        break;
      }
      var cis1 = Math.floor(((Math.random()*990)+10))/10;
      var zcis1 = Math.floor((Math.random()*delka.length));
      var zcis2 = Math.floor((Math.random()*delka.length));
      if(zcis1 == zcis2) continue;
      var znam1 = delka[zcis1];
      var znam2 = delka[zcis2];
      var rozdil = delky[znam1].length - delky[znam2].length;
      if(Math.abs(rozdil)>6) continue;
      var nasobek = Math.pow(10,rozdil);
      var vysledek = Math.round(cis1*nasobek*1000000)/1000000; 
      
      
      if(!priklady[0]){
        priklady[0] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else if(!testShodyPrvADruh(priklady, cis1+" "+znam1, znam2)){
        priklady[citac] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else {
        continue;
      }
      citac++;
    }
    
    return priklady;
  }
  
    function prevodObjemu(pocet){
    var priklady = new Array;
    var citac = 0;
    var moc = 0;
    var delka = new Array('mm3','cm3','dm3','m3','ml','dl','l','hl','km3');
    var delky = new Array;
    delky['mm3'] = "1";
    delky['cm3'] = "1000";
    delky['ml'] = "1000";
    delky['dl'] = "100000";
    delky['dm3'] = "1000000";
    delky['l'] = "1000000";
    delky['hl'] = "100000000"
    delky['m3'] = "1000000000";
    delky['km3'] = "1000000000000000000";
    
    while(citac != pocet){
      if(moc++ > 5000){
        break;
      }
      var cis1 = Math.floor(((Math.random()*990)+10))/10;
      var zcis1 = Math.floor((Math.random()*delka.length));
      var zcis2 = Math.floor((Math.random()*delka.length));
      if(zcis1 == zcis2) continue;
      var znam1 = delka[zcis1];
      var znam2 = delka[zcis2];
      var rozdil = delky[znam1].length - delky[znam2].length;
      if(Math.abs(rozdil)>6) continue;
      var nasobek = Math.pow(10,rozdil);
      var vysledek = Math.round(cis1*nasobek*1000000)/1000000; 
      
      
      if(!priklady[0]){
        priklady[0] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else if(!testShodyPrvADruh(priklady, cis1+" "+znam1, znam2)){
        priklady[citac] = new PrikladPorov(cis1+" "+znam1, znam2, vysledek);
      } else {
        continue;
      }
      citac++;
    }
    
    return priklady;
  }
  
  function prevodDelkyPlochy(pocet){
    pr1 = new Array;
    pul = pocet/2;
    pr1 = prevodDelky(pul);
    pr2 = new Array;
    pr2 = prevodPlochy(pul);
    for(i=0; i<pul; i++){
      index = i + pul;
      pr1[index] = pr2[i];
    }
    return pr1;
  }
  
  function prevodDPO(pocet){
    pr1 = new Array;
    pr2 = new Array;
    pr3 = new Array;
    ctvrt = Math.round((pocet/3));
    zbytek = pocet - (ctvrt*2);
    pr1 = prevodObjemu(ctvrt);
    pr2 = prevodPlochy(ctvrt);
    pr3 = prevodDelky(zbytek);
    
    for(i=0; i<ctvrt; i++){
      id = i+ctvrt;
      pr1[id] = pr2[i];
    }
    dvaCt = ctvrt*2;
    for(i=0; i<zbytek; i++){
      id = i+dvaCt;
      pr1[id] = pr3[i];
    }
    return pr1;
  }
  
  
-->  
