js日历-面向对象

function Calender()
			{
				var str="日,一,二,三,四,五,六";
				weekArray=str.split(',');
				var now=new Date();
				this.year=now.getFullYear();
				this.day=now.getDay();
				this.month=now.getMonth()+1;
				this.date=now.getDate();
				
			
				
				//定义输出函数
				this.print=function()
				{
			
				//输出第一行
				  var lineStr="<div style='width:200px' align='center'>"+
				                   this.year+"年"+this.month+"月"
								   ;
					
		         if(this.isRunYear(this.year))
				 lineStr+="(闰)</div>";
				 lineStr+="<div align='center'>星期"+weekArray[this.day];
				 lineStr+="</div>";
				 //输出今天的日期
				 dateStr="<div align='center'><h1>"+this.date+"</h1></div>";
				 
			     //日历星期和日期的对应
				 var weeks="<div align='center'><table><tr>";
				 for (var i = 0; i < weekArray.length; i++)
				 {
			 	 weeks += "<td>" + weekArray[i] + "</td>";
				 }
				  weeks+="</tr>";
				  var firstday=new Date(this.year+"/"+this.month+"/1");
				  var fweek=firstday.getDay();
				  theday=now.getDate();
				  daynum=this.haveDays(this.year,this.month);
				  for(var j=1;j<7;j++)
				  {
				  	weeks+="<tr>";
					for(var i=0;i<7;i++)
					{
						theday=7*(j-1)+i+1-fweek;
				  	if ((j==0)&&i<(fweek)||(theday>daynum)||theday<=0)
					    weeks+="<td>&nbsp;</td>";
					else
					   weeks+="<td>"+theday+"</td>";
					}
				  weeks+="</tr>";
			     
				  }
				
				weeks+="</table></div>";
			    document.writeln(lineStr);
				document.writeln(dateStr);
				document.writeln(weeks);	
				}
				//得到年该月的第一天是星期几
			    this.getFirstDay=function()
				 {
				 	var firstday=new Date(this.year+"/"+this.month+"/1");
					return firstday.getDate();
				 }
				//检查是否是闰年
				this.isRunYear=function(year)
				{
					if((year%400==0)||((year%4==0)&&(year%100!=0)))
					return true;
					else
					return false;
				}
				//判断这某年某月有几天
				this.haveDays=function(year,month)
				{
				
					var result=0;
					switch(month)
					{
						case 1:
						case 3:
						case 5:
						case 7:
						case 8:
						case 10:
						case 12:result=31;break;
						case 4:
						case 6:
						case 9:
						case 11:result=30;break;
						case 2:result=(isRunYear(year))?29:28;break;
					}
					return result;
				}
			
			}
		
			window.onload=function()
			{
                var calender=new Calender();
			    calender.print();
			
			}