课程表上一周下一周

var currDT;
var aryDay = new Array("日", "一", "二", "三", "四", "五", "六");

//初始页面 
function initWeek() {
    currDT = new Date();
    showDate();
}

//上一周 或 下一周 
function addWeek(ope) {
    var num = 0;
    if (ope == "-") {
        num = -7;
    }
    else if (ope == "+") {
        num = 7;
    }
    currDT = addDate(currDT, num);
    //showDate();
    return currDT;
}

function showDate() {
    //span1.innerHTML = currDT.toLocaleDateString(); //显示日期 
    var dw = currDT.getDay();
    var tdDT;
    //确定周一是那天 
    if (dw == 0) {
        tdDT = addDate(currDT, -6);
    }
    else {
        tdDT = addDate(currDT, (1 - dw));
    }
    //在表格中显示一周的日期 
    var objTB = document.getElementById("trWeek");
    for (var i = 0; i < 7; i++) {
        if (tdDT.toLocaleDateString() == currDT.toLocaleDateString()) {
            objTB.cells[i + 1].style.color = "red"; //currDT突出显示 
        }
        dw = tdDT.getDay();
        objTB.cells[i + 1].innerHTML = "星期" + aryDay[dw] + "<br />[" + tdDT.getFullYear() + "-" + (tdDT.getMonth() + 1) + "-" + tdDT.getDate() + "]";
        tdDT = addDate(tdDT, 1); //下一天 
    }
}

//增加或减少若干天，由 num 的正负决定，正为加，负为减 
function addDate(dt, num) {
    var ope = "+";
    if (num < 0) {
        ope = "-";
    }

    var reDT = dt;
    for (var i = 0; i < Math.abs(num) ; i++) {
        reDT = addOneDay(reDT, ope);
    }
    return reDT;
}

//增加或减少一天，由ope决定, + 为加，- 为减，否则不动 
function addOneDay(dt, ope) {
    var num = 0;
    if (ope == "-") {
        num = -1;
    }
    else if (ope == "+") {
        num = 1;
    }

    var y = dt.getFullYear();
    var m = dt.getMonth();
    var lastDay = getLastDay(y, m);

    var d = dt.getDate();
    d += num;
    if (d < 1) {
        m--;
        if (m < 0) {
            y--;
            m = 11;
        }
        d = getLastDay(y, m);
    }
    else if (d > lastDay) {
        m++;
        if (m > 11) {
            y++;
            m = 0;
        }
        d = 1;
    }

    var reDT = new Date();
    reDT.setYear(y);
    reDT.setMonth(m);
    reDT.setDate(d);

    return reDT;
}

//是否为闰年 
function isLeapYear(y) {
    var isLeap = false;
    if (y % 4 == 0 && y % 100 != 0 || y % 400 == 0) {
        isLeap = true;
    }
    return isLeap;
}

//每月最后一天 
function getLastDay(y, m) {
    var lastDay = 28;
    m++;
    if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12) {
        lastDay = 31;
    }
    else if (m == 4 || m == 6 || m == 9 || m == 11) {
        lastDay = 30;
    }
    else if (isLeapYear(y) == true) {
        lastDay = 29;
    }
    return lastDay;
}
//获取任意周的开始时间
function getAnyWeekStart(date) {
    var currentDay = date.getDay();
    if (currentDay == 0) { currentDay = 7; }
    var mondayTime = date.getTime() - (currentDay - 1) * 24 * 60 * 60 * 1000;
    var startTime = new Date(mondayTime).toLocaleDateString();
    return startTime;
    
}
//获取任意周的结束时间
function getAnyWeekEnd(date) {
    var currentDay = date.getDay();
    if (currentDay == 0) { currentDay = 7; }
    var sundayTime = date.getTime() + (7 - currentDay) * 24 * 60 * 60 * 1000;
    var endTime = new Date(sundayTime).toLocaleDateString();
    return endTime;
}