6.24 年月日三级联动和显示当前时间

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<html lang="zh">
<head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
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    <script src="../public/jquery-3.3.1.min.js" type="text/javascript" charset="utf-8"></script>
    <title>Document</title>
</head>
<body>
    <select id="nian" onchange="changeTian()">
        
    </select><select id="yue" onchange="changeTian()">
        
    </select><select id="tian">
        
    </select><div id="shijian">
        
    </div>
</body>
</html>
<script type="text/javascript">
    nian();
    yue();
    tian();
    showTime();
    function showTime(){
         var nowTime = new Date();
         $("#shijian").html(nowTime.toLocaleString());//Sun Jun 24 2018 19:41:21 GMT+0800 转成2018/6/24 下午7:42:09
         setTimeout("showTime()",1000);//用于在指定的毫秒数后调用函数或计算表达式。
    }
    function nian(){
        var nowtime = new Date();//获取系统当前时间 
        var nian = nowtime.getFullYear();//获取当前年份
        var str = "";
        for(var i=1900;i<=2020;i++){
            if(i==nian){
                str +="<option selected>"+i+"</option>"
            }else{
                str +="<option>"+i+"</option>";
            }
        }$("#nian").html(str);    
    }
    function yue(){
        var myDate = new Date();
        var month=myDate.getMonth()+1;//获取当前月
        var str ="";
        for(var i =1;i<=12;i++){
            if(i==month){
                str +="<option selected>"+i+"</option>"
                             //选中当前月
            }else{
                str +="<option>"+i+"</option>";
            }
        }
        $("#yue").html(str);
    }
    function tian(){
        var nian = $("#nian").val();
        var yue = $("#yue").val();
        var ts =30;
        if(yue==1||yue==3||yue==5||yue==7||yue==8||yue==10||yue==12){
                 ts = 31;
          }else if(yue==2){
              if((nian%4==0&&nian%100 !=0)||nian%400==0){
                  ts = 29;
              }else{
                  ts=28;
              }
          }
          var str ="";
          for(var i=1;i<=ts;i++){
              str+="<option>"+i+"</option>";
          }
          $("#tian").html(str);
    }
    function changeTian(){
        tian();
    }
    

    
    
    
    </script> 

原文地址:https://www.cnblogs.com/sunhao1987/p/9221542.html