var   objYear=null;   
var   objMonth=null;   
var   objDate=null;   
/*   
    *页面初始化   
    */   
function   init(name1,name2,name3,a,b,c){   
var   dlts1   =   document.getElementsByName(name1);   
var   dlts2   =   document.getElementsByName(name2);
var   dlts3   =   document.getElementsByName(name3);
objYear=dlts1[0];   
objMonth=dlts2[0];   
objDate=dlts3[0];  


objYear.attachEvent("onchange",YearChg);   
objMonth.attachEvent("onchange",MonthChg);   
var   date   =   new   Date();   
if (a!=''){var   curYear=a;}else{var   curYear=date.getYear();}

if (b!=''){var   curMonth=b;}else{var   curMonth=date.getMonth()+1;  }

if (c!=''){var   curDate=c;}else{var   curDate=date.getDate(); }
  
if(objYear   ==   null   ||   objMonth   ==   null   ||   objDate   ==   null   ){   
alert("Can't   find   object!");     
return   false;   
}   
var   str="";   

initDltValue(objYear,1950,2020);   
initDltValue(objMonth,1,12);   
initDltValue(objDate,1,CalDays(curYear,curMonth));   

objYear.value=curYear;   
objMonth.value=curMonth;   
objDate.value=curDate;   
    
}     
/*   
    *添加select的option值   
    */   
function   initDltValue(obj,min,max){   
for(var   i=min;i<=max;i++)   
optAdd(obj,i);   
}  

/*   
    *当年份改变的时候   
    */   
function   YearChg(){   
var   dateVal=objDate.value;   
objDate.innerHTML="";   
initDltValue(objDate,1,CalDays(parseInt(objYear.value),parseInt(objMonth.value)));   
objDate.value=dateVal;   
if(objDate.selectedIndex==-1)   objDate.selectedIndex=0;   
}   
/*   
    *当月份改变的时候   
    */   
function   MonthChg(){   
objDate.innerHTML="";   
initDltValue(objDate,1,CalDays(parseInt(objYear.value),parseInt(objMonth.value)));   
}   
/*   
    *设置对象的disabled属性   
    */   
function   setDisabled(a,b,c){   
objYear.disabled=a;   
objMonth.disabled=b;   
objDate.disabled=c;   
}   
/*   
    *为select对象添加option   
    */   
function   optAdd(obj,val){   
var   newOpt=document.createElement("option");   
obj.add(newOpt);   
newOpt.value=val;   
newOpt.text=val;   
}   
/*   
    *根据年月计算天数   
    */   
function   CalDays(year,mon){   
var   date=   new   Date(year,mon,0);   
return   date.getDate();   
    
}