原生JS面向对象方法实现万年历

###面向对象的方法实现万年历
实现思路:
   1.创建构造函数constructor
   ```
   function Calender(main){
        this.currentDate = new Date()
        this.main = main;
    }
   ```
   2.创建日历对象的prototype方法
   ```
   Calender.prototype = {
        constructor: Calender,
        //创建主体内容区域
        showMain:function(){},
        //创建标题头区域
        showHeader: function(){},   
        //创建week标题头
        showWeek: function(){}, 
        //创建容纳日期的容器
        showDate:function(){},
        //封装一个方法,待点击切换月份时,初始化页面
        showInit: function(){}
    };//对象结束
   ```
   3.实现思路:
      
``` ==> 创建日历对象的主体内容
       showMain:function(){
            var $t = this;//将this对象缓存到$t中,this指向Calender对象
            
            $t.main = document.createElement("main")
            document.body.appendChild($t.main);
            $t.main.style.width = "600px";
            $t.main.style.height = "600px";
            $t.main.style.backgroundColor = "gray";
            $t.main.style.margin = "50px auto";
            $t.main.style.borderRadius = '15px'
        }
```
``` ==> 创建标题头区域(包含切换按钮/年月)
       showHeader: function(){
            var $t = this;
            //左控制键
            var prevSpan = document.createElement('span')
            $t.main.appendChild(prevSpan)
            prevSpan.innerHTML = '<'
            
            //存放年月信息
            var span = document.createElement('span')
            $t.main.appendChild(span)
            
            //右控制键
            var nextSpan = document.createElement('span')
            $t.main.appendChild(nextSpan)
            nextSpan.innerHTML = '>'
            
            var allSpan = document.querySelectorAll('span')
            var month = $t.currentDate.getMonth() + 1
            var year = $t.currentDate.getFullYear()
            
            //设置左边年月信息
            span.innerHTML = year + '年' + month + '月'
            for(var i = 0; i < allSpan.length; i++) {
                var span = allSpan[i]
                //设置span的css样式
                span.style.display = 'inline-block'
                span.style.width = '33.3%';
                span.style.height = '100px'
                span.style.color = 'white'
                span.style.fontSize = '30px'
                span.style.textAlign = 'center'
                span.style.lineHeight = '100px'
                span.id = 'index' + i
                
                //为左右按键添加事件
                if(i==0 || i==2) {
                    span.onclick = function() {
                        month = $t.currentDate.getMonth()
                        year = $t.currentDate.getFullYear()
                        if(this.id == 'index0') {
                            month--
                        } else if(this.id == "index2") {
                            month++
                        }
                    //点击完重新设置当前月
                    $t.currentDate.setMonth(month)
                    //清空页面
                    document.body.innerHTML = ''
                    //重新布局
                    $t.showInit()
                    }
                }
            };      
        }
```
     
``` ==> 创建week标题头
      showWeek: function(){
            var $t = this;
            //创建table标签
            var table = document.createElement('table')
            $t.main.appendChild(table)
            table.style.width = '100%'
            //往表格里边添加一行
            var tr = table.insertRow()
            var weeks = ['日','一', '二', '三', '四', '五', '六' ]
            for(var i = 0; i < weeks.length; i++) {
                //往tr插入列
                var td = tr.insertCell()
                td.style.height = '50px'
                td.style.backgroundColor = 'goldenrod'
                td.style.textAlign = 'center'
                td.innerHTML = weeks[i]
            }
        },
```
     
```==> 创建容纳日期的容器
      showDate:function(){
            var $t = this;
            var table = document.createElement('table')
            $t.main.appendChild(table)
            table.style.width = '100%'
            
            //创建一个名言标签
            var  p = document.createElement("p")
            $t.main.appendChild(p)
            p.innerHTML = "每一天都是新的自己,怎么活,自己决定!"
            p.style.fontSize = "24px";
            p.style.width = "100%";
            p.style.height = "60px";
            p.style.lineHeight = "30px"
            p.style.textAlign = "center"
            p.style.color = "white"
            
            //创建日期容器
            for(var i = 0; i < 6; i++) {
                //创建6行
                var tr = table.insertRow()
                for(var k = 0; k < 7; k++) {
                    //每一行7格
                    var td = tr.insertCell()
                    td.style.height = '60px'
                    td.style.backgroundColor = 'orange'
                    td.style.textAlign = 'center'
                    td.style.fontSize = "20px"
                    var dayIndex = i * 7 + k
                    
                    //计算每一个格所对应的日期对象
                    var eachDate = getEveryDate(dayIndex)
                    //得到每一个日期的号数
                    td.innerHTML = eachDate.getDate()
                    
                    //获取当天日期的值,突出显示当天日期
                    var now = new Date()
                    var currentDay = now.getDate()
                    //console.log(currentDay)
                    if(eachDate.getMonth() == now.getMonth() && eachDate.getDate() ===currentDay)
                        td.style.backgroundColor = "aquamarine"
                    
                    //判断当前月和推算出来的日期的月份是否一样,不一样则代表不是当前月的日期,则把日期灰色显示
                    if(eachDate.getMonth() != $t.currentDate.getMonth()) {
                        td.style.backgroundColor = 'lightgray'
                        td.style.color = 'gray'
                    }
                }
            }
        },
```
``` ==> 封装一个方法,待点击切换月份时,初始化页面
      //封装一个方法,待点击切换月份时,初始化页面
        showInit: function(){
            var $t = this;
            $t.showMain()
            $t.showHeader()
            $t.showWeek()
            $t.showDate()
        }
```
     
```  ==> 对象实例化和初始化页面
        //实例化一个Calender对象
        var calender = new Calender()
    
        calender.showInit()//初始化页面
```
 
源代码地址:github地址==》https://github.com/Hasyou99/Calender
看的故事多了,才慢慢知道,话说多了就是打自己的脸!
原文地址:https://www.cnblogs.com/alex-415/p/6810745.html