js怎么算出年龄

<script type="text/javascript">
    var csrq = '1995-10-07';
    var age = '';
    var d = new Date();
    var year = d.getFullYear();
    var month = d.getMonth() + 1;
    var day = d.getDate();
    if (month < 10) {
        month = '0'+month;
    }
    if(day < 10){
        day = '0'+day;
    }
    var now = year+'-'+month+'-'+day;
    if (now.substring(0,4) >= csrq.substring(0,4) && now.substring(5,7) >=csrq.substring(5,7) 
        && now.substring(8,10)>=csrq.substring(8,10)) {
        age = year - parseInt(csrq.substring(0,4));
    }else{
        age = year - parseInt(csrq.substring(0,4)) - 1;
    }
    //alert(age);
</script>

ps：来源网络