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                        /前端开发
                        
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                        /JavaScript进阶篇

请教关于日期函数的问题

function window_onload()
{
   var myForm = document.form1;
   var nowDate = new Date();
   myForm.firstDay.options[nowDate.getDate()-1].selected = true;
   myForm.secondDay.options[nowDate.getDate()-1].selected =true;
    myForm.secondMonth.options[nowDate.getMonth()].selected =true;
   myForm.firstMonth.options[nowDate.getMonth()].selected = true;
   myForm.firstYear.options[nowDate.getFullYear()-1970].selected =true;
   myForm.secondYear.options[nowDate.getFullYear()-1970].selected =true;
}
//可以执行，返回firstDay，secondDay.options【】对象的值为当前时间，，
function window_onload()
{
   var myForm = document.form1;
   var nowDate = new Date();
   myForm.firstDay.options[nowDate.getDate()-1].selected = true;
   myForm.firstMonth.options[nowDate.getMonth()].selected = true;
   myForm.firstYear.options[nowDate.getFullYear()-1970].selected =true;
   myForm.secondDay.options[nowDate.getDate()-1].selected =true;
   myForm.secondMonth.options[nowDate.getMonth()].selected =true;
   myForm.secondYear.options[nowDate.getFullYear()-1970].selected =true;
}

顺序更改后，firstDay 正常返回当前日期，secondDay则无法返回当前日期，为什么？？？