function checkForm( form) {
	var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;	
	var numExp = /^[0-9\ \.\-]+$/;
	var alphanumExp = /^[^!\?#%\*;<>=\[\]\^\{\}\|~]+$/;
	
	if (form.product.value=='') { alert("Please select product you are registering."); form.product.focus(); return false;}
	if (form.product.value=='Other' && form.other_product.value=='') { alert("Please enter product you are registering."); form.other_product.focus(); return false;}
	if (form.serno.value=='') { alert("Please enter serial number."); form.serno.focus(); return false;}
	if (!form.serno.value.match(numExp)) { alert("Please enter correct serial number (000-000000)"); form.serno.focus(); return false;}
	if (form.name.value=='') { alert("Please enter customer (company name)."); form.name.focus(); return false;}
	if (form.city.value=='') { alert("Please enter city."); form.city.focus(); return false;}
	if (form.country.value=='') { alert("Please select country."); form.country.focus(); return false;}
	if (form.contact_f.value=='') { alert("Please enter your first name."); form.contact_f.focus(); return false;}
	if (!form.contact_f.value.match(alphanumExp)) { alert("Please don't use special characters in your first name."); form.contact_f.focus(); return false;}
	if (form.contact_f.value.length > 80) { alert("Please enter first name at least 80 characters long."); form.contact_f.focus(); return false;}
	if (form.contact_l.value=='') { alert("Please enter your last name."); form.contact_l.focus(); return false;}
	if (!form.contact_l.value.match(alphanumExp)) { alert("Please don't use special characters in your last name."); form.contact_l.focus(); return false;}
	if (form.contact_l.value.length > 80) { alert("Please enter last name at least 80 characters long."); form.contact_l.focus(); return false;}
	if (form.email.value=='') { alert("Please enter your E-mail."); form.email.focus(); return false;}
	if (!form.email.value.match(emailExp)) { alert("Your E-mail address is not valid."); form.email.focus(); return false;}
	if (form.email.value!=form.conf_email.value) { alert("Your E-mail addresses don't match. Please, check your E-mail."); form.email.focus(); return false;}
	if (form.buy_product[0].checked==false && form.buy_product[1].checked==false && form.buy_product[2].checked==false) { alert("Please enter where you bought the product."); form.buy_product[0].focus(); form.buy_product[0].checked=false; return false;}
	if (form.buy_product[0].checked==true && form.purchase.value=='') { alert("Please enter where you bought the product."); form.purchase.focus(); return false;}
	if (form.buy_product[2].checked==true && form.other_specify.value=='') { alert("Please enter where you bought the product."); form.other_specify.focus(); return false;}
	if (form.purchdate.value=='') { alert("Please enter date of purchasing."); form.purchdate.focus(); return false;}
	if (form.pc[0].checked==false && form.pc[1].checked==false && form.pc[2].checked==false && form.pc[3].checked==false && form.pc[4].checked==false) {alert("Please select what type of computer you are using."); form.pc[0].focus(); form.pc[0].checked=false;  return false;}
	if (form.pc[4].checked==true && form.other_pc.value=='') { alert("Please enter what type of computer you are using."); form.other_pc.focus(); return false; }
	if (form.pcvariant[0].checked==false && form.pcvariant[1].checked==false) { alert("Please select whether Desktop or Notebook you have.");form.pcvariant[0].focus();form.pcvariant[0].checked=false; return false; }
	if (form.MS_DOS.checked==false && form.WIN_3x.checked==false && form.WIN_95.checked==false && form.WIN_98.checked==false && form.WIN_Me.checked==false && form.WIN_NT.checked==false && form.WIN_2000.checked==false && form.WIN_XP.checked==false && form.WIN_2003.checked==false && form.WIN_XPx64.checked==false && form.WIN_Vista.checked==false) { alert("Please select operating system you are using.");form.MS_DOS.focus(); form.MS_DOS.checked=false; return false; }
	if (form.hear[0].checked==false && form.hear[1].checked==false && form.hear[2].checked==false && form.hear[3].checked==false && form.hear[4].checked==false) { alert("Please select where you heard about ELNEC.");form.hear[0].focus();form.hear[0].checked=false; return false; }
	if (form.hear[4].checked==true && form.hear_other.value=='') { alert("Please enter where you heard about ELNEC.");form.hear_other.focus();return false;}
	if (form.price.checked==false && form.quality.checked==false && form.recomend.checked==false && form.features.checked==false) {alert("Please enter why you chose this product.");form.price.focus();form.price.checked=false;return false;}
	if (form.features.checked==true && form.fetures_spec.value=='') { alert("Please enter why you chose this product.");form.fetures_spec.focus();return false; }
	if (form.already_work[0].checked==false && form.already_work[1].checked==false) { alert("Please enter if you already work in the past with Elnec programmer"); form.already_work[0].focus(); form.already_work[0].checked=false; return false; }
	if (form.already_work[0].checked==true && form.already_work_with.value=='') { alert("Please enter type of ELNEC programmer which you already work with."); form.already_work_with.focus(); return false; }
	if (form.already_have[0].checked==false && form.already_have[1].checked==false) { alert("Please enter if you have some of Elnec programmer"); form.already_have[0].focus(); form.already_have[0].checked=false; return false; }
	if (form.already_have[0].checked==true && form.already_have_with.value=='') { alert("Please enter type of your ELNEC programmer."); form.already_have_with.focus(); return false; }
	if (form.security_code.value=='') { alert("Please enter control code from picture."); form.security_code.focus(); return false;}
	
	return true;
}

function checkFormSk( form) {
  	var emailExp = /^[\w\-\.\+]+\@[a-zA-Z0-9\.\-]+\.[a-zA-z0-9]{2,4}$/;	
	var numExp = /^[0-9\ \.\-]+$/;
	var alphanumExp = /^[^!\?#%\*;<>=\[\]\^\{\}\|~]+$/;	

	if (form.product.value=='') { alert("Prosím vyberte výrobok, ktorý registrujete."); form.product.focus(); return false;}
	if (form.product.value=='Iné' && form.other_product.value=='') { alert("Prosím zadajte výrobok, ktorý registrujete."); form.other_product.focus(); return false;}
	if (form.serno.value=='') { alert("Prosím zadajte sériové číslo."); form.serno.focus(); return false;}
	if (!form.serno.value.match(numExp)) { alert("Prosím zadajte správne sériové číslo (000-000000)"); form.serno.focus(); return false;}
	if (form.name.value=='') { alert("Prosím vyplňte položku zákazník (meno spoločnosti)."); form.name.focus(); return false;}
	if (form.city.value=='') { alert("Prosím vyplňte položku mesto."); form.city.focus(); return false;}	
	if (form.country.value=='') { alert("Prosím vyberte ‘tát."); form.country.focus(); return false;}
	if (form.contact_f.value=='') { alert("Prosím zadajte Va‘e meno."); form.contact_f.focus(); return false;}
	if (!form.contact_f.value.match(alphanumExp)) { alert("Prosím nepoužívajte ‘peciálne znaky vo Va‘om mene."); form.contact_f.focus(); return false;}
	if (form.contact_f.value.length > 80) { alert("Prosím zadajte Va‘e meno na max. 80 znakov."); form.contact_f.focus(); return false;}
	if (form.contact_l.value=='') { alert("Prosím zadajte Va‘e priezvisko."); form.contact_l.focus(); return false;}
	if (!form.contact_l.value.match(alphanumExp)) { alert("Prosím nepoužívajte ‘peciálne znaky vo Va‘om priezvisku."); form.contact_l.focus(); return false;}
	if (form.contact_l.value.length > 80) { alert("Prosím zadajte Va‘e priezvisko na max. 80 znakov."); form.contact_l.focus(); return false;}
	if (form.email.value=='') { alert("Prosím zadajte Va‘u E-mailovú adresu."); form.email.focus(); return false;}
	if (!form.email.value.match(emailExp)) { alert("Va‘a E-mailová adresa je nesprávna."); form.email.focus(); return false;}
	if (form.email.value!=form.conf_email.value) { alert("Zadané E-mailové adresy nie sú rovnaké. Prosím skontrolujte Váą E-mail."); form.email.focus(); return false;}
	if (form.buy_product[0].checked==false && form.buy_product[1].checked==false && form.buy_product[2].checked==false) { alert("Prosím zadajte kde ste zakúpili výrobok."); form.buy_product[0].focus(); form.buy_product[0].checked=false; return false;}
	if (form.buy_product[0].checked==true && form.purchase.value=='') { alert("Prosím zadajte kde ste zakúpili výrobok."); form.purchase.focus(); return false;}
	if (form.buy_product[2].checked==true && form.other_specify.value=='') { alert("Prosím zadajte kde ste zakúpili výrobok."); form.other_specify.focus(); return false;}
	if (form.purchdate.value=='') { alert("Prosím zadajte dátum zakúpenia."); form.purchdate.focus(); return false;}
	if (form.pc[0].checked==false && form.pc[1].checked==false && form.pc[2].checked==false && form.pc[3].checked==false && form.pc[4].checked==false) {alert("Prosím vyberte typ Váąho PC."); form.pc[0].focus(); form.pc[0].checked=false;  return false;}
	if (form.pc[4].checked==true && form.other_pc.value=='') { alert("Prosím zadajte typ Váąho PC."); form.other_pc.focus(); return false; }
	if (form.pcvariant[0].checked==false && form.pcvariant[1].checked==false) { alert("Prosím vyberte či máte Desktop alebo Notebook.");form.pcvariant[0].focus();form.pcvariant[0].checked=false; return false; }
	if (form.MS_DOS.checked==false && form.WIN_3x.checked==false && form.WIN_95.checked==false && form.WIN_98.checked==false && form.WIN_Me.checked==false && form.WIN_NT.checked==false && form.WIN_2000.checked==false && form.WIN_XP.checked==false && form.WIN_2003.checked==false && form.WIN_XPx64.checked==false && form.WIN_Vista.checked==false) { alert("Prosím vyberte aký operačný systém pouľívate.");form.MS_DOS.focus(); form.MS_DOS.checked=false; return false; }
	if (form.hear[0].checked==false && form.hear[1].checked==false && form.hear[2].checked==false && form.hear[3].checked==false) { alert("Prosím vyberte ako ste sa dozvedeli o firme ELNEC.");form.hear[0].focus();form.hear[0].checked=false; return false; }
	if (form.hear[3].checked==true && form.hear_other.value=='') { alert("Prosím zadajte ako ste sa dozvedeli o firme ELNEC.");form.hear_other.focus();return false;}
	if (form.Cena.checked==false && form.Kvalita.checked==false && form.Odp_kolegov.checked==false && form.Vlas_skusenost.checked==false && form.Ine.checked==false) {alert("Prosím zadajte prečo ste sa rozhodli pre tento výrobok.");form.Cena.focus();form.Cena.checked=false;return false;}
	if (form.Ine.checked==true && form.fetures_spec.value=='') { alert("Prosím zadajte prečo ste sa rozhodli pre tento výrobok.");form.fetures_spec.focus();return false; }
	if (form.already_work[0].checked==false && form.already_work[1].checked==false) { alert("Prosím zadajte či ste niekedy pracovali s ELNEC programátormi"); form.already_work[0].focus(); form.already_work[0].checked=false; return false; }
	if (form.already_work[0].checked==true && form.already_work_with.value=='') { alert("Prosím zadajte typ programátora s ktorým ste pracovali."); form.already_work_with.focus(); return false; }
	if (form.already_have[0].checked==false && form.already_have[1].checked==false) { alert("Prosím zadajte či vlastníte niektorý z ELNEC programátorov"); form.already_have[0].focus(); form.already_have[0].checked=false; return false; }
	if (form.already_have[0].checked==true && form.already_have_with.value=='') { alert("Prosím zadajte typ Vá‘ho ELNEC programátora."); form.already_have_with.focus(); return false; }
	if (form.security_code.value=='') { alert("Prosím vložte kontrolný kód z obrázka."); form.security_code.focus(); return false;}
	
	return true;
}