function changeSelectPro(o) {
tip=document.getElementById('f_tip').value;
tiptxt=document.getElementById('f_tiptxt').value;
proizv=o.value;
protxt=o.options[o.selectedIndex].text;
 
    stro="catalog.php?tip="+tip+"&proizv="+proizv+"&protxt="+protxt+"&tiptxt="+tiptxt;
    objWindow=window.open(stro,"_self");
}

function changeSelectTip(o) {

proizv=document.getElementById('f_pro').value;
protxt=document.getElementById('f_protxt').value;

tip=o.value;
tiptxt=o.options[o.selectedIndex].text;
  
    stro="catalog.php?tip="+tip+"&proizv="+proizv+"&protxt="+protxt+"&tiptxt="+tiptxt;
    objWindow=window.open(stro,"_self");
}