[jQuery] inArray not working with dates

[jQuery] inArray not working with dates


Can someone tell me what I may be doing wrong here?
    var dateList = new Array();
    dateList.push(new Date(2009,7-1,29));
    dateList.push(new Date(2009,7-1,30));
    dateList.push(new Date(2009,7-1,31));
    var testdate = new Date(2009,7-1,30);
    alert($.inArray(testdate,dateList)); //returns -1 ????
tia,
Dave