javascript獲得當前月的天數

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<html>
<head>
<title> New Document </title>
<meta name="Generator" content="EditPlus">
<meta name="Author" content="">
<meta name="Keywords" content="">
<meta name="Description" content="">
</head>

<body>
<script type="text/javascript">
<!--
function m_DaysInMonth(pYear,pMonth){
    var nDays = 30;
    if(pMonth==2){    //2月单独处理
        if(m_IsLeap(pYear)) nDays = 29;
        else nDays = 28;
    }
    else if(mInList(pMonth,"1,3,5,7,8,10,12")){
        nDays = 31;
    }
    return nDays;
}

//判断某年是否是闰年
function m_IsLeap(pYear){
    if(pYear % 400 == 0){
        return true;
    }
    else if((pYear % 100 != 0) && (pYear % 4 == 0)){
        return true;
    }
    return false;
}

//判断是否在字符串列表里：
// if(mInList("3","1,3,5,7,8,10,12")){ //true
// if(mInList("2","1,3,5,7,8,10,12")){ //false

function mInList(s1,slist){
   var ss1=","+s1+",";
   var ss2=","+slist+",";
   ss1 = ss1.toLowerCase();
   ss2 = ss2.toLowerCase();
   return ss2.indexOf(ss1)!=-1;
}
alert(m_DaysInMonth(2011,2));

//-->
</script>
</body>
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