function kontrola(form){ 
	if(form.name.value == ""){
		alert("Zadejte prosím uživatelské jméno");
		form.name.focus();
		form.name.className = "err2";
		return false;
	}else if(form.pass.value == ""){
		alert("Zadejte Vaše heslo");
		form.pass.focus();
		form.pass.className = "err2";
		form.name.className = "";
		return false;
	}else if(form.pass2.value == ""){
		alert("Zadejte prosím Váše heslo pro kontrolu ještě jednou");
		form.pass2.focus();
		form.pass2.className = "err2";
		form.pass.className = "";
		form.name.className = "";
		return false;
	}else if(form.pass.value != form.pass2.value){
		alert("Hesla se musejí shodovat !");
		form.pass.focus();
		form.pass.className = "err2";
		form.name.className = "";
		return false;
	}else if(form.email.value == "" || form.email.value == "@" || form.email.value.indexOf('@')==-1 || form.email.value.indexOf('.')==-1){
		alert("Zadejte prosím Váš e-mail");
		form.email.focus();
		form.email.className = "err2";
	  form.pass.className = "";
	  form.pass2.className = "";
		form.name.className = "";
		return false;
	}else{
return true;  
	}
}