How to redirect based on value of dropdown?

Hi
How do i make a HTML form redirect to different pages based on responses to a form?I have a HTML form with two drop down boxes with the options ‘Yes’ and ‘No’ in each. When submitted, i want the form to direct the user to one page if both responses are yes, and another page if either response is no.
<snip/>

In your onsubmit even handler include some code similar to this demo

 
    sel1O = document.getElementById("sel_1");
    sel2O = document.getElementById("sel_2");
    formO = document.getElementById("form_id");
 
 if(sel1O.value == 'yes' && sel2O.value == 'yes') {
     formO.action="url_1";
    } else if (sel1O.value == 'no' && sel2O.value == 'no') {
     formO.action="url_2";
    } else {
     formO.action="url_3";
    }
 return true;