Java小项目之：教你做电子日历！

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var days = new Array("日","一","二","三","四","五","六");//星期
var today = new Date();//当天日期，备用
var month_big = new Array("1","3","5","7","8","10","12"); //包含所有大月的数组
var month_small = new Array("4","6","9","11"); //包含所有小月的数组
var separator = "-";//间隔符

var calendar = document.getElementById("calendar");
var cal_parent = calendar.parentNode;//获取父元素
var cal_width = ((calendar.clientWidth<150) ? 150 : calendar.clientWidth);//获取input的宽度，如果input宽度小于150，调整为150，150为日历块最小宽度
var cal_height = calendar.clientHeight;//获取input的高度，整数
var cal_X = calendar.offsetLeft;//获取input左边 距父元素的距离，整数
var cal_Y = calendar.offsetTop;//获取input顶部 距父元素的距离，整数

calendar.style.cursor = "pointer";//将input的鼠标设置成小手
calendar.readOnly = "readOnly";//设置input为只读
calendar.onblur = hideCalendar; //当input失去焦点时，隐藏cal_body
calendar.onclick = showCalendar;//点击input时调用showCalendar函数

//取input宽度的七分之一再减一作为方格的边长
var pane_height = cal_width/7 - 1;

function hideCalendar(){
var cal_body = document.getElementById("cal_body");
if(cal_body != undefined){
cal_body.parentNode.removeChild(cal_body);
}
}

//显示日历主体
function showCalendar(){
var cal_body = document.getElementById("cal_body");
if(cal_body != undefined){
cal_body.parentNode.removeChild(cal_body);
}
else{
var cal_body = document.createElement("DIV");
cal_body.id = "cal_body";
cal_body.style.width = cal_width + "px";
cal_body.style.height = "auto";
cal_body.style.overflow = "hidden";
cal_body.style.position = "absolute";
cal_body.style.zIndex = "9";
cal_body.style.left = cal_X + "px";
cal_body.style.top = (cal_Y + cal_height + 5) + "px";
cal_body.style.border = "solid 1px #CCCCCC";
//鼠标移动到cal_body上时，禁用input的onblur事件，防止cal_body因input失去焦点而被隐藏
cal_body.onmouseover = function(){
calendar.onblur = undefined;
}
//鼠标从cal_body移除时，启用input的onblur事件，并且先让input获得焦点，否则当在cal_body上空白处点击后再移出在其他地方点击时，input因没有焦点而无法触发onblur事件
cal_body.onmouseout = function(){
calendar.focus();
calendar.onblur = hideCalendar;
}
cal_parent.appendChild(cal_body);

    var line1 = document.createElement("DIV");
    line1.style.width = cal_width + "px";
    line1.style.height =  pane_height + "px";
    line1.style.backgroundColor = "#0FF";

    var btn1 = document.createElement("DIV");
    btn1.style.width = (cal_width/3 - 3) + "px";
    btn1.style.height = pane_height + "px";
    btn1.style.lineHeight = pane_height + "px";
    btn1.style.textAlign = "center";
    btn1.innerHTML = "<";
    btn1.style.cursor = "pointer";
    btn1.style.cssFloat = "left";
    btn1.onclick = function(){
        if(isValidated()){
            var old_year = parseInt(document.getElementById("input_year").value);
            if(old_year > 1960){
                var year = old_year - 1;
                var month = parseInt(document.getElementById("input_month").value);
                var val = year + separator + month + separator + 1;
                init(val);
            }
        }
    };
    line1.appendChild(btn1);

    var input_year = document.createElement("INPUT");
    input_year.id = "input_year";
    input_year.style.width = (cal_width/3) + "px";
    input_year.style.height = "70%";
    input_year.style.cssFloat = "left";
    input_year.style.textAlign = "center";
    input_year.onchange = function(){
        changed();
    };
    line1.appendChild(input_year);

    var btn2 = document.createElement("DIV");
    btn2.style.width = (cal_width/3 - 3) + "px";
    btn2.style.height = pane_height + "px";
    btn2.style.lineHeight = pane_height + "px";
    btn2.style.textAlign = "center";
    btn2.innerHTML = ">";
    btn2.style.cursor = "pointer";
    btn2.style.cssFloat = "left";
    btn2.onclick = function(){
        if(isValidated()){
            var old_year = parseInt(document.getElementById("input_year").value);
            if(old_year < 2050){
                var year = old_year + 1;
                var month = parseInt(document.getElementById("input_month").value);
                var val = year + separator + month + separator + 1;
                init(val);
            }
        }
    };
    line1.appendChild(btn2);

    var line2 = document.createElement("DIV");
    line2.style.width = cal_width + "px";
    line2.style.height =  pane_height + "px";
    line2.style.backgroundColor = "#0FF";

    var btn3 = document.createElement("DIV");
    btn3.style.width = (cal_width/3 - 3) + "px";
    btn3.style.height = pane_height + "px";
    btn3.style.lineHeight = pane_height + "px";
    btn3.style.textAlign = "center";
    btn3.innerHTML = "<";
    btn3.style.cursor = "pointer";
    btn3.style.cssFloat = "left";
    btn3.onclick = function(){
        if(isValidated()){
            var old_month = parseInt(document.getElementById("input_month").value)
            if(old_month > 1){
                var year = parseInt(document.getElementById("input_year").value);
                var month = old_month - 1;
                var val = year + separator + month + separator + 1;
                init(val);
            }
            else {
                var year = parseInt(document.getElementById("input_year").value) - 1;
                var month = 12;
                var val = year + separator + month + separator + 1;
                init(val);
            }
        }
    };
    line2.appendChild(btn3);

    var input_month = document.createElement("INPUT");
    input_month.id = "input_month";
    input_month.style.width = (cal_width/3) + "px";
    input_month.style.height = "70%";
    input_month.style.cssFloat = "left";
    input_month.style.textAlign = "center";
    input_month.onchange = function(){
        changed();
    };
    line2.appendChild(input_month);

    var btn4 = document.createElement("DIV");
    btn4.style.width = (cal_width/3 - 3) + "px";
    btn4.style.height = pane_height + "px";
    btn4.style.lineHeight = pane_height + "px";
    btn4.style.textAlign = "center";
    btn4.innerHTML = ">";
    btn4.style.cursor = "pointer";
    btn4.style.cssFloat = "left";
    btn4.onclick = function(){
        if(isValidated()){
            var old_month = parseInt(document.getElementById("input_month").value)
            if(old_month < 12){
                var year = parseInt(document.getElementById("input_year").value);
                var month = parseInt(document.getElementById("input_month").value) + 1;
                var val = year + separator + month + separator + 1;
                init(val);
            }
            else {
                var year = parseInt(document.getElementById("input_year").value) + 1;
                var month = 1;
                var val = year + separator + month + separator + 1;
                init(val);
            }
        }
    };
    line2.appendChild(btn4);

    cal_body.appendChild(line1);
    cal_body.appendChild(line2);

    for(var i=0; i < 7; i++){
        var pane = document.createElement("DIV");
        pane.className = "pane";
        pane.style.width = pane_height + "px";
        pane.style.height = pane_height + "px";
        pane.style.lineHeight = pane_height + "px";
        pane.style.textAlign = "center";
        pane.style.cssFloat = "left";
        pane.innerHTML = days[i];
        cal_body.appendChild(pane);
    }
    init(calendar.value);
}

}

function init(val){
clearPane();

var cal_body = document.getElementById("cal_body");
var temp_date;
var year;
var month;
var date;

if(val == ""){
    temp_date = today;
    calendar.value = today.toFormatString(separator);
}
else{
    year = val.year();
    month = val.month(separator);
    date = val.date(separator);
    temp_date = new Date(year,month,date);
}

year = temp_date.getFullYear();
month = temp_date.getMonth() + 1;
date = temp_date.getDate();
temp_date.setDate(1);

var start = temp_date.getDay() + 7;
var end;

if(array_contain(month_big, month)){
    end = start + 31;
}
else if(array_contain(month_small, month)){
    end = start + 30;
}
else{
    if(isLeapYear(year)){
        end = start + 29;
    }
    else{
        end = start + 28;
    }
}

for(var i = 7; i < start; i++){
    var pane = document.createElement("DIV");
    pane.className = "pane";
    pane.style.width = pane_height + "px";
    pane.style.height = pane_height + "px";
    pane.style.lineHeight = pane_height + "px";
    pane.style.textAlign = "center";
    pane.style.cssFloat = "left";
    cal_body.appendChild(pane);
}

for(var i = start; i < end; i++){
    var pane = document.createElement("DIV");
    pane.className = "pane";
    pane.style.width = pane_height + "px";
    pane.style.height = pane_height + "px";
    pane.style.lineHeight = pane_height + "px";
    pane.style.textAlign = "center";
    pane.style.cssFloat = "left";
    pane.innerHTML = i - start + 1;
    pane.style.cursor = "pointer";
    pane.onmouseover = function(){
        this.style.backgroundColor = '#0FF';
    }
    if(date == (i - start + 1))
        pane.style.backgroundColor = '#0FF';
    else{
        pane.onmouseout = function(){
            this.style.backgroundColor = '';
        }
    }
    pane.onclick = function(){
        calendar.value = year + separator + month + separator + this.innerHTML;
        cal_body.parentNode.removeChild(cal_body);
    }
    cal_body.appendChild(pane);

    document.getElementById("input_year").value = year;
    document.getElementById("input_month").value = month;
}

}

//格式化输出
Date.prototype.toFormatString = function(separator){
var result = this.getFullYear() + separator + (this.getMonth() + 1) + separator + this.getDate();
return result;
};

//从格式化字符串中获取年份
String.prototype.year = function(){
var str = this.substring(0,4);
return str;
};

//从格式化字符串中获取月份
String.prototype.month = function(separator){
var start = this.indexOf(separator) + 1;
var end = this.lastIndexOf(separator);
return parseInt(this.substring(start, end)) - 1;
};

//从格式化字符串中获取日期
String.prototype.date = function(separator){
var start = this.lastIndexOf(separator) + 1;
return this.substring(start);
};

//判断数组array中是否包含元素obj的函数，包含则返回true，不包含则返回false
function array_contain(array, obj){
for (var i = 0; i < array.length; i++){
if (array[i] == obj)
return true;
}
return false;
}

//判断年份year是否为闰年，是闰年则返回true，否则返回false
function isLeapYear(year){
var a = year % 4;
var b = year % 100;
var c = year % 400;
if( ( (a == 0) && (b != 0) ) || (c == 0) ){
return true;
}
return false;
}

//清除方格
function clearPane(){
var limit = document.getElementsByClassName("pane").length;
for(var i=7; i < limit; i++){
var pane = document.getElementsByClassName("pane").item(7);
pane.parentNode.removeChild(pane);
}
}

//判断输入是否合法
function isValidated(){
var year = document.getElementById("input_year").value;
var month = document.getElementById("input_month").value;
if(isNaN(year) || isNaN(month)){
alert("请输入正确的年份/月份");
return false;
}
else{
if(year%1 != 0 || month%1 != 0){
alert("请输入正确的年份/月份");
return false;
}
else{
year = parseInt(year);
if(year < 1960 || year > 2050){
alert("请输入1960~2050之间的年份！");
return false;
}
else if(month < 1 || month >12){
alert("请输入正确的月份！");
return false;
}
else{
return true;
}
}
}
}

//年份月份发生变化时处理函数
function changed(){
if(isValidated()){
var year = document.getElementById("input_year").value;
var month = document.getElementById("input_month").value;
var val = year + separator + month + separator + 1;
init(val);
}
}
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新闻标题：Java小项目之：教你做电子日历！
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