<script language=javascript>
String.prototype.isDate = function()
{
var r = this.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);
if(r==null)return false; var d = new Date(r[1], r[3]-1, r[4]);
return(d.getFullYear()==r[1]&&(d.getMonth()+1)==r[3]&&d.getDate()==r[4]);
}
alert("2005-12-50".isDate());
alert("2005-12-30".isDate());
</script>
String.prototype.isDate = function()
{
var r = this.match(/^(\d{1,4})(-|\/)(\d{1,2})\2(\d{1,2})$/);
if(r==null)return false; var d = new Date(r[1], r[3]-1, r[4]);
return(d.getFullYear()==r[1]&&(d.getMonth()+1)==r[3]&&d.getDate()==r[4]);
}
alert("2005-12-50".isDate());
alert("2005-12-30".isDate());
</script>
"http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312">
<title>月份之差</title>
</head>
a = new Date("2004/1/1")
b = new Date("2004/10/1")
alert("月份间隔：" + parseInt((b-a)/1000/24/60/60/30))