Hello! I want to write a simple function for my visitors. They have to choose hours. and I have something like that: <script type="text/javascript"> function Godzina() { var godzina = document.getElementById('godzina'); var wartgodz = document.getElementById('wartgodz'); switch (godzina.value) { case '0' : wartgodz.innerHTML = 'From hour: <select name="godzina"><option value=\"$go:00\">$go:00</option><option value=\"$go:30\">$go:30</option></select><br>To: <select name="godzina2"></option>"; ><option value=\"$go:00\">$go:00</option><option value=\"$go:30\">$go:30</option></select>'; break; // I deleted my PHP code from here case 'wyb' : wartgodz.innerHTML = ''; break; default : wartgodz.innerHTML = 'wartgodz.innerHTML = 'From hour: <select name="godzina"><option value=\"$go:00\">$go:00</option><option value=\"$go:30\">$go:30</option></select><br>To: <select name="godzina2"></option>"; ><option value=\"$go:00\">$go:00</option><option value=\"$go:30\">$go:30</option></select>'; break;'; break; // I deleted my PHP code from here } } </script> HTML: But I want to "godzina2" tag to be +3 hour's bigger than "godzina" chosen by user How to do that?