Setting default value through javascript

i want to change the default value of dropdown list to 0 i.e selected index value shud become 0 when press the cancel button so that watever i selected previously is removed
i want it in javascipt only...i have done it in c#...since there s no forum for javascript i posted here only

here is the javsacript

Code:

    function CloseDiv() {
            var control = document.getElementById("divReqStages");
            control.style.visibility = "hidden";
            var control1 = document.getElementById('DDLReqStages').selectedIndex;
            control1.value='0';
         
        }

here s the asp code....when i click here the drop down shud be reset