纯JS写出日历

封装代码：

(function(cmf){
    cmf.showDcalendar=function(){
        var fnname=cmf.fn
        var id="cmfrili2"
        var yy=f23timeselecta1.value,mm=f23timeselecta2.value-1
        var newdara=new Date()
        var dd=newdara.getDate();
        var d=new Date(yy,mm,1),t
        if(mm==0){mm=12;yy--}
        var a,b,c,d2
        t='<table width=100% onselectstart="return false"><tr align=center>'
        var ds='<font color=#ff0000>日</font>,一,二,三,四,五,<font color="#009900">六</font>'.split(",")
        for(x=0;x<7;x++)t+='<td><b>'+ds[x]+'</b></td>'
        t+='</tr><tr>'
        //计算显示上个月有几号在日历上
        a=d.getDay()
        if(a==0)a=7
        r=[]
        var c2=0
        for(var x=0;x<a;x++)
        {
            d2=new Date(d-24*3600*1000*(a-x))
            r[r.length]="1"+d2.getDate()
            c2++
        }

    //计算显示这个月有几号在日历上
        mm++
        if(mm==13){mm=1;yy++}
        c=cmf.getMonthM(yy,mm)//计算哪年哪月 有多少天

        d=new Date(yy,mm,1)
        for(var x=1;x<=c;x++)r[r.length]="2"+x

      //计算显示下个月有几号在日历上
        c2+=c//r数组有多少个

        d2=new Date(yy,mm-1,c)

        a=d2.getDay()//这个月最后一天星期几

        a=7-a
        if(c2<36)a+=7

        for(var x=1;x<a;x++)
        {
            r[r.length]="3"+x
        }
        var yy1=yy.toString()
        var mm1=mm.toString()
        for(var x=0;x<r.length;x++)
        {

            if(x%7==0)t+='<tr align=center>'
            t+='<td height=25 onclick="'+fnname+'('+yy1+mm1+r[x].toString().substring(1)+',this)" onmouseover=this.bgColor="#33eeff" onmouseout=this.bgColor=""'
            if(r[x]=="2"+dd)t+=' style="border:1px solid #aa0000"'
            t+='>'
            var cl=""
            if(r[x].charAt(0)!=2)cl='999999'
            else if(x%7==0)cl='ff0000'
            else if(x%7==6)cl='009900'
            if(cl!="")t+='<font color="#'+cl+'">'
            t+=r[x].substring(1)
            if(cl!="")t+='</font>'
            t+='</td>'
            if(x%7==6)t+='</tr>'

        }
        t+='</table>'

        document.getElementById(id).innerHTML=t
    }

    cmf.getMonthM=function(y,m){//计算哪年哪月 有多少天 月份从1开始
        if(m==4 || m==6 || m==9 || m==11)return 30
        if(m==2)return (y%4==0 && y%100!=0)|| y%400==0?29:28
        return 31
    }
    cmf.showd=function(id,fn){
        cmf.fn=fn
        var g='<div id="cmfrili1"></div><div id="cmfrili2"></div>'
        var newdara=new Date()
        var yy=newdara.getFullYear();
        var mm=newdara.getMonth()+1;
        document.getElementById(id).innerHTML=g
        var s='border-width:1px;border-style:solid;border-color:#000000 #cccccc #cccccc #000000;width: 44px;'
        var t=''
        +'<table bgcolor="#ffffff" width=100% cellpadding=0 cellspacing=0><tr align=center><td height=44>'
        +cmf.timeselect_ms(1,'<input type=text value="'+yy+'" id="f23timeselecta1" onchange="cmf.showDcalendar()"  style="width:44;text-align:center;'+s+'">年')
        +'</td><td>'
        +cmf.timeselect_ms(2,'<input type=text value="'+mm+'" id="f23timeselecta2" onchange="cmf.showDcalendar()"  style="width:22;text-align:center;'+s+'">月')
        +'</td>'
        document.getElementById("cmfrili1").innerHTML=t
        cmf.showDcalendar()

    }
    cmf.timeselect_ms=function(n,m,n2)
    {
        var t='<table cellpadding=0 cellspacing=0 height=20><tr align=center>'
        t+='<td onmouseup="cmf.timeselect_up('+n+',2)" onselectstart="return false" style="font-size:16px;cursor:pointer;"><b>◄</b></td>'
        if(m!=null)t+='<td>'+m+'</td>'
        t+='<td onmouseup="cmf.timeselect_up('+n+',1)"  onselectstart="return false" style="font-size:16px;cursor:pointer;"><b>►</b></td>'
        if(n2!=null)t+='<td>'+n2+'</td>'
        t+='</tr></table>'
        return t
    }

    cmf.timeselect_up=function(n,m){
        var o=document.getElementById("f23timeselecta"+n),c=o.value
        if(c=="")c=1
        if(n==1)//年
        {
            if(m==2){//减
                c--
            }else if(m==1){//加
                c++
            }
        }
        else
        {
            if(m==2){//减
                if(c<2)  return
                c--
            }else if(m==1){//加
                if(c==12) return
                c++
            }
        }
        o.value=c
        if(m==1 || m==2)cmf.showDcalendar()
    }
})(window.cmf={})

使用：

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>日历</title>
        <script src="Dcalendar.js" type="text/javascript" charset="utf-8"></script>
        <script src="http://libs.baidu.com/jquery/2.0.0/jquery.min.js"></script>

    </head>
    <body>
        <div id="ri" style="width: 400px;">

        </div>
    </body>
    <script type="text/javascript">
        cmf.showd('ri','dianji')
        function dianji(d,ti){
            $("#ri td").css('border','')
            $(ti).css('border','1px solid #aa0000')
            alert(d)
        }
    </script>
</html>

使用代码中dianji()函数是用户点击某天弹出某天的日期；效果如下