javaScript给日期加一天

<script language="javascript">
    function test(){
                var mm="2011-10-10";
	var arr = mm.split("-");
	var newdt = new Date(Number(arr[0]),Number(arr[1])-1,Number(arr[2])+1);
	repnewdt = newdt.getFullYear() + "-" +   (newdt.getMonth()+1) + "-" + newdt.getDate();
	alert(repnewdt);
   }
   test();
</script>

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