Javascript/Jquery实现日期前一天后一天

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<html xmlns="http://www.w3.org/1999/xhtml" lang="en">

    <head>

        <meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />

        <title></title>

        <script type="text/javascript" src="js/jquery-1.8.2.js" ></script>

    </head>

    <body>

        <a id="test2" href="javascript: void(0);">前一天</a>

        测试日期:<span id="test1">20200301</span>

        <a id="test3" href="javascript: void(0);">后一天</a>

        <script type="text/javascript">

            function getDateArr(year){

                var yearFlag = false;

                var januaryQty = 31;

                var dateArr = [];

                dateArr.push(januaryQty);

                var februaryQty = 28;

                if((year % 100 == 0

                    && year % 400 == 0)

                    || (year % 4 == 0

                    && year % 100 != 0)){

                    februaryQty = 29;

                }

                dateArr.push(februaryQty);

                var marchQty = 31;

                var aprilQty = 30;

                var mayQty = 31;

                var juneQty = 30;

                var julyQty = 31;

                var augustQty = 31;

                var septemberQty = 30;

                var octoberQty = 31;

                var novemberQty = 30;

                var decemberQty = 31;

                dateArr.push(marchQty);

                dateArr.push(aprilQty);

                dateArr.push(mayQty);

                dateArr.push(juneQty);

                dateArr.push(julyQty);

                dateArr.push(augustQty);

                dateArr.push(septemberQty);

                dateArr.push(octoberQty);

                dateArr.push(novemberQty);

                dateArr.push(decemberQty);

                return dateArr;

            }

            $("#test2").on("click", function(){

                 var currentDateStr = $("#test1").text();

                 var currentYearStr = currentDateStr.substring(0, 4);

                 var dateArr = getDateArr(currentYearStr);

                 var currentMonthStr = currentDateStr.substring(4, 6);

                 var currentDayStr = currentDateStr.substring(6);

                 var currentMonthDayQty = dateArr[currentMonthStr - 1];

                 var priviousMonthDayIndex = currentMonthStr - 2;

                 if(priviousMonthDayIndex == -1){

                     priviousMonthDayIndex = dateArr.length - 1;

                 }

                 if(priviousMonthDayIndex == 12){

                     priviousMonthDayIndex = 0;

                 }

                 var priviousMonthDayQty = dateArr[priviousMonthDayIndex];

                 var previousYear = parseInt(currentYearStr);

                 var previousMonth = parseInt(currentMonthStr);

                 var previousDay = parseInt(currentDayStr) - 1;

                 var previousYearStr = previousYear + "";

                 var previousMonthStr = previousMonth + "";

                 var previousDayStr = previousDay + "";

                 if(previousDayStr < 1){

                     previousDayStr = priviousMonthDayQty;

                     previousMonthStr = parseInt(previousMonthStr) - 1;

                 }

                 if(previousMonthStr == 0){

                     previousYearStr = parseInt(previousYearStr) - 1;

                     previousMonthStr = 12;

                 }

                 if(previousMonthStr < 10){

                     previousMonthStr = "0" + previousMonthStr;

                 }

                 if(previousDayStr < 10){

                     previousDayStr = "0" + previousDayStr;

                 }

                 var previousDateStr = previousYearStr.toString() + previousMonthStr.toString() + previousDayStr.toString();

                 $("#test1").text(previousDateStr);

            });

            $("#test3").on("click", function(){

                 var currentDateStr = $("#test1").text();

                 var currentYearStr = currentDateStr.substring(0, 4);

                 var dateArr = getDateArr(currentYearStr);

                 var currentMonthStr = currentDateStr.substring(4, 6);

                 var currentDayStr = currentDateStr.substring(6);

                 var currentMonthDayQty = dateArr[currentMonthStr - 1];

                 var nextMonthDayIndex = currentMonthStr;

                 var nextYear = parseInt(currentYearStr);

                 var nextMonth = parseInt(currentMonthStr);

                 var nextDay = parseInt(currentDayStr) + 1;

                 if(nextDay > currentMonthDayQty){

                     nextDay = 1;

                     nextMonth = parseInt(nextMonth) + 1;

                 }

                 if(nextMonth == 13){

                     nextYear = parseInt(nextYear) + 1;

                     nextMonth = 1;

                 }

                 var nextYearStr = nextYear + "";

                 var nextMonthStr = nextMonth + "";

                 if(nextMonthStr < 10){

                     nextMonthStr = "0" + nextMonthStr;

                 }

                 var nextDayStr = nextDay + "";

                 if(nextDayStr < 10){

                     nextDayStr = "0" + nextDayStr;

                 }

                 var nextDateStr = nextYearStr.toString() + nextMonthStr.toString() + nextDayStr.toString();

                 $("#test1").text(nextDateStr);

            });

        </script>

    </body>

</html>
Javascript/Jquery实现日期前一天后一天-LMLPHP
已完成.