function comment(form) {
 if(form.jmeno.value=="") {
    alert('Nezadali jste jméno!');
	form.jmeno.focus();
	return false;
 }else if(form.email.value=="") {
    alert('Nezadali jste email!');
	form.email.focus();
	return false;
 }else if(form.text.value=="") {
    alert('Nezadali jste text!');
	form.text.focus();
	return false;
 }else if(window.RegExp) {
      re=new RegExp("^[^@]+@[^.]+\.[^.]+$");
      if(!re.test(form.email.value)) {
          alert('Email není platný!');
		  form.email.focus();
	      return false;
	  }
 }else {
    return true;
 }
}