<html> <head> <title>年月日三下拉框联动</title> <meta http-equiv='Content-Type' content='text/html; charset=gb2312'> </head> <body> <form name="reg_testdate"> <select name="YYYY" onchange="YYYYDD(this.value)"> <option value="">请选择 年</option> </select> <select name="MM" onchange="MMDD(this.value)"> <option value="">选择 月</option> </select> <select name="DD"> <option value="">选择 日</option> </select> </form> <script language="JavaScript"><!-- function YYYYMMDDstart() { MonHead = [31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31]; //先给年下拉框赋内容 var y = new Date().getFullYear(); for (var i = (y-30); i < (y+30); i++) //以今年为准，前30年，后30年 document.reg_testdate.YYYY.options.add(new Option(" "+ i +" 年", i)); //赋月份的下拉框 for (var i = 1; i < 13; i++) document.reg_testdate.MM.options.add(new Option(" " + i + " 月", i)); document.reg_testdate.YYYY.value = y; document.reg_testdate.MM.value = new Date().getMonth() + 1; var n = MonHead[new Date().getMonth()]; if (new Date().getMonth() ==1 && IsPinYear(YYYYvalue)) n++; writeDay(n); //赋日期下拉框Author:meizz document.reg_testdate.DD.value = new Date().getDate(); } if(document.attachEvent) window.attachEvent("onload", YYYYMMDDstart); else window.addEventListener('load', YYYYMMDDstart, false); function YYYYDD(str) //年发生变化时日期发生变化(主要是判断闰平年) { var MMvalue = document.reg_testdate.MM.options[document.reg_testdate.MM.selectedIndex].value; if (MMvalue == ""){ var e = document.reg_testdate.DD; optionsClear(e); return;} var n = MonHead[MMvalue - 1]; if (MMvalue ==2 && IsPinYear(str)) n++; writeDay(n) } function MMDD(str) //月发生变化时日期联动 { var YYYYvalue = document.reg_testdate.YYYY.options[document.reg_testdate.YYYY.selectedIndex].value; if (YYYYvalue == ""){ var e = document.reg_testdate.DD; optionsClear(e); return;} var n = MonHead[str - 1]; if (str ==2 && IsPinYear(YYYYvalue)) n++; writeDay(n) } function writeDay(n) //据条件写日期的下拉框 { var e = document.reg_testdate.DD; optionsClear(e); for (var i=1; i<(n+1); i++) e.options.add(new Option(" "+ i + " 日", i)); } function IsPinYear(year)//判断是否闰平年 { return(0 == year%4 && (year%100 !=0 || year%400 == 0));} function optionsClear(e) { e.options.length = 1; } //--></script> </body> </html>