js日期选择器，自动填充日期

[javascript]代码库
<html>
<head>
<title>JS日期选择器</title>
<script type="text/javascript">
    function HS_DateAdd(interval, number, date) {
        number = parseInt(number);
        if (typeof (date) == "string") {
            var date = new Date(date.split("-")[0], date.split("-")[1], date
                    .split("-")[2])
        }
        if (typeof (date) == "object") {
            var date = date
        }
        switch (interval) {
        case "y":
            return new Date(date.getFullYear() + number, date.getMonth(), date
                    .getDate());
            break;
        case "m":
            return new Date(date.getFullYear(), date.getMonth() + number,
                    checkDate(date.getFullYear(), date.getMonth() + number,
                            date.getDate()));
            break;
        case "d":
            return new Date(date.getFullYear(), date.getMonth(), date.getDate()
                    + number);
            break;
        case "w":
            return new Date(date.getFullYear(), date.getMonth(), 7 * number
                    + date.getDate());
            break;
        }
    }
    function checkDate(year, month, date) {
        var enddate = [ "31", "28", "31", "30", "31", "30", "31", "31", "30",
                "31", "30", "31" ];
        var returnDate = "";
        if (year % 4 == 0) {
            enddate[1] = "29"
        }
        if (date > enddate[month]) {
            returnDate = enddate[month]
        } else {
            returnDate = date
        }
        return returnDate;
    }
 
    function WeekDay(date) {
        var theDate;
        if (typeof (date) == "string") {
            theDate = new Date(date.split("-")[0], date.split("-")[1], date
                    .split("-")[2]);
        }
        if (typeof (date) == "object") {
            theDate = date
        }
        return theDate.getDay();
    }
    function HS_calender() {
        var lis = "";
        var style = "";
        style += "<style type='text/css'>";
        style += ".calender { width:170px; height:auto; font-size:12px; margin-right:14px; background:url(calenderbg.gif) no-repeat right center #fff; border:1px solid #397EAE; padding:1px}";
        style += ".calender ul {list-style-type:none; margin:0; padding:0;}";
        style += ".calender .day { background-color:#EDF5FF; height:20px;}";
        style += ".calender .day li,.calender .date li{ float:left; width:14%; height:20px; line-height:20px; text-align:center}";
        style += ".calender li a { text-decoration:none; font-family:Tahoma; font-size:11px; color:#333}";
        style += ".calender li a:hover { color:#f30; text-decoration:underline}";
        style += ".calender li a.hasArticle {font-weight:bold; color:#f60 !important}";
        style += ".lastMonthDate, .nextMonthDate {color:#bbb;font-size:11px}";
        style += ".selectThisYear a, .selectThisMonth a{text-decoration:none; margin:0 2px; color:#000; font-weight:bold}";
        style += ".calender .LastMonth, .calender .NextMonth{ text-decoration:none; color:#000; font-size:18px; font-weight:bold; line-height:16px;}";
        style += ".calender .LastMonth { float:left;}";
        style += ".calender .NextMonth { float:right;}";
        style += ".calenderBody {clear:both}";
        style += ".calenderTitle {text-align:center;height:20px; line-height:20px; clear:both}";
        style += ".today { background-color:#ffffaa;border:1px solid #f60; padding:2px}";
        style += ".today a { color:#f30; }";
        style += ".calenderBottom {clear:both; border-top:1px solid #ddd; padding: 3px 0; text-align:left}";
        style += ".calenderBottom a {text-decoration:none; margin:2px !important; font-weight:bold; color:#000}";
        style += ".calenderBottom a.closeCalender{float:right}";
        style += ".closeCalenderBox {float:right; border:1px solid #000; background:#fff; font-size:9px; width:11px; height:11px; line-height:11px; text-align:center;overflow:hidden; font-weight:normal !important}";
        style += "</style>";
 
        var now;
        if (typeof (arguments[0]) == "string") {
            selectDate = arguments[0].split("-");
            var year = selectDate[0];
            var month = parseInt(selectDate[1]) - 1 + "";
            var date = selectDate[2];
            now = new Date(year, month, date);
        } else if (typeof (arguments[0]) == "object") {
            now = arguments[0];
        }
        var lastMonthEndDate = HS_DateAdd("d", "-1",
                now.getFullYear() + "-" + now.getMonth() + "-01").getDate();
        var lastMonthDate = WeekDay(now.getFullYear() + "-" + now.getMonth()
                + "-01");
        var thisMonthLastDate = HS_DateAdd("d", "-1", now.getFullYear() + "-"
                + (parseInt(now.getMonth()) + 1).toString() + "-01");
        var thisMonthEndDate = thisMonthLastDate.getDate();
        var thisMonthEndDay = thisMonthLastDate.getDay();
        var todayObj = new Date();
        today = todayObj.getFullYear() + "-" + todayObj.getMonth() + "-"
                + todayObj.getDate();
 
        for (i = 0; i < lastMonthDate; i++) { // Last Month's Date
            lis = "<li class='lastMonthDate'>" + lastMonthEndDate + "</li>"
                    + lis;
            lastMonthEndDate--;
        }
        for (i = 1; i <= thisMonthEndDate; i++) { // Current Month's Date
 
            if (today == now.getFullYear() + "-" + now.getMonth() + "-" + i) {
                var todayString = now.getFullYear() + "-"
                        + (parseInt(now.getMonth()) + 1).toString() + "-" + i;
                lis += "<li><a href=javascript:void(0) class='today' onclick='_selectThisDay(this)' title='"
                        + now.getFullYear()
                        + "-"
                        + (parseInt(now.getMonth()) + 1)
                        + "-"
                        + i
                        + "'>"
                        + i
                        + "</a></li>";
            } else {
                lis += "<li><a href=javascript:void(0) onclick='_selectThisDay(this)' title='"
                        + now.getFullYear()
                        + "-"
                        + (parseInt(now.getMonth()) + 1)
                        + "-"
                        + i
                        + "'>"
                        + i
                        + "</a></li>";
            }
 
        }
        var j = 1;
        for (i = thisMonthEndDay; i < 6; i++) { // Next Month's Date
            lis += "<li class='nextMonthDate'>" + j + "</li>";
            j++;
        }
        lis += style;
 
        var CalenderTitle = "<a href='javascript:void(0)' class='NextMonth' onclick=HS_calender(HS_DateAdd('m',1,'"
                + now.getFullYear()
                + "-"
                + now.getMonth()
                + "-"
                + now.getDate() + "'),this) title='Next Month'>&raquo;</a>";
        CalenderTitle += "<a href='javascript:void(0)' class='LastMonth' onclick=HS_calender(HS_DateAdd('m',-1,'"
                + now.getFullYear()
                + "-"
                + now.getMonth()
                + "-"
                + now.getDate() + "'),this) title='Previous Month'>&laquo;</a>";
        CalenderTitle += "<span class='selectThisYear'><a href='javascript:void(0)' onclick='CalenderselectYear(this)' title='Click here to select other year' >"
                + now.getFullYear()
                + "</a></span>年<span class='selectThisMonth'><a href='javascript:void(0)' onclick='CalenderselectMonth(this)' title='Click here to select other month'>"
                + (parseInt(now.getMonth()) + 1).toString() + "</a></span>月";
 
        if (arguments.length > 1) {
            arguments[1].parentNode.parentNode.getElementsByTagName("ul")[1].innerHTML = lis;
            arguments[1].parentNode.innerHTML = CalenderTitle;
 
        } else {
            var CalenderBox = style
                    + "<div class='calender'><div class='calenderTitle'>"
                    + CalenderTitle
                    + "</div><div class='calenderBody'><ul class='day'><li>日</li><li>一</li><li>二</li><li>三</li><li>四</li><li>五</li><li>六</li></ul><ul class='date' id='thisMonthDate'>"
                    + lis
                    + "</ul></div><div class='calenderBottom'><a href='javascript:void(0)' class='closeCalender' onclick='closeCalender(this)'>×</a><span><span><a href=javascript:void(0) onclick='_selectThisDay(this)' title='"
                    + todayString + "'>Today</a></span></span></div></div>";
            return CalenderBox;
        }
    }
    function _selectThisDay(d) {
        var boxObj = d.parentNode.parentNode.parentNode.parentNode.parentNode;
        boxObj.targetObj.value = d.title;
        boxObj.parentNode.removeChild(boxObj);
    }
    function closeCalender(d) {
        var boxObj = d.parentNode.parentNode.parentNode;
        boxObj.parentNode.removeChild(boxObj);
    }
 
    function CalenderselectYear(obj) {
        var opt = "";
        var thisYear = obj.innerHTML;
        for (i = 1970; i <= 2020; i++) {
            if (i == thisYear) {
                opt += "<option value="+i+" selected>" + i + "</option>";
            } else {
                opt += "<option value="+i+">" + i + "</option>";
            }
        }
        opt = "<select onblur='selectThisYear(this)' onchange='selectThisYear(this)' style='font-size:11px'>"
                + opt + "</select>";
        obj.parentNode.innerHTML = opt;
    }
 
    function selectThisYear(obj) {
        HS_calender(obj.value
                + "-"
                + obj.parentNode.parentNode.getElementsByTagName("span")[1]
                        .getElementsByTagName("a")[0].innerHTML + "-1",
                obj.parentNode);
    }
 
    function CalenderselectMonth(obj) {
        var opt = "";
        var thisMonth = obj.innerHTML;
        for (i = 1; i <= 12; i++) {
            if (i == thisMonth) {
                opt += "<option value="+i+" selected>" + i + "</option>";
            } else {
                opt += "<option value="+i+">" + i + "</option>";
            }
        }
        opt = "<select onblur='selectThisMonth(this)' onchange='selectThisMonth(this)' style='font-size:11px'>"
                + opt + "</select>";
        obj.parentNode.innerHTML = opt;
    }
    function selectThisMonth(obj) {
        HS_calender(obj.parentNode.parentNode.getElementsByTagName("span")[0]
                .getElementsByTagName("a")[0].innerHTML
                + "-" + obj.value + "-1", obj.parentNode);
    }
    function HS_setDate(inputObj) {
        var calenderObj = document.createElement("span");
        calenderObj.innerHTML = HS_calender(new Date());
        calenderObj.style.position = "absolute";
        calenderObj.targetObj = inputObj;
        inputObj.parentNode.insertBefore(calenderObj, inputObj.nextSibling);
    }
</script>
 
</head>
<body>
<h3>js日期选择器，自动填充日期</h3>
 
日期：
<input type="text" style="width: 70px" onfocus="HS_setDate(this)">
 
</body>
</html>
[代码运行效果截图]