我有 3 个下拉列表框，year、month和day。
我需要填充从当前日期开始的最后 1095 天的值。目前，我通过在带有日历系统表的 SQL 中运行查询来做到这一点。有没有办法直接在javascript中做到这一点？
我使用 SQL 的原因是从今天开始的 1095 天内我无法关联 3 个下拉框。例如，假设今天是 2009 年 9 月 6 日。如果我为 选择 2009 year，那么month下拉列表应该从 9 月开始，day下拉列表应该从 6 开始。
我需要用户能够灵活地选择过去 1095 天中的任何日期。所以首先用户选择 2009 .only 然后应该填充月份下拉框。它应该只有从 9 月到 12 月的月份。然后选择月份为9 月只有 1 到 30 应该填充在天下拉框中。我目前正在通过使用 sql 中的系统日期表来执行此操作。
代码有点困难，但恕我直言，以下效果很好。做了两个类似的函数，第一个调用onload初始化所有三个选择框，第二个在onchange事件发生时调用：
function init_dates() {
var now = new Date();
var newest = [];
newest[0] = now.getFullYear();
newest[1] = now.getMonth() + 1;
newest[2] = now.getDate();
var old = new Date(now.getTime() - 1095 * 86400 * 1000);
var oldest = [];
oldest[0] = old.getFullYear();
oldest[1] = old.getMonth() + 1;
oldest[2] = old.getDate();
// YEARS
var opt;
var i = oldest[0];
var year = document.getElementById('year');
while (i <= newest[0]) {
opt = document.createElement('option');
opt.value = i;
opt.innerHTML = i;
if (i == newest[0]) {
opt.selected = 'selected';
}
year.appendChild(opt);
i++;
}
// MONTHS
var minmonth = (year.value == oldest[0]) ? oldest[1] : 1;
var maxmonth = (year.value == newest[0]) ? newest[1] : 12;
var month = document.getElementById('month');
while (minmonth <= maxmonth) {
opt = document.createElement('option');
opt.value = minmonth;
opt.innerHTML = minmonth;
month.appendChild(opt);
minmonth++;
}
// DAYS
var minday = (year.value == oldest[0] && month.value == oldest[1]) ? oldest[2] : 1;
var maxday = (year.value == newest[0] && month.value == newest[1]) ? newest[2] : 33;
if (maxday == 33) {
// find correct maxday
maxday = 27;
var d = new Date(year.value, month.value - 1, maxday, 0, 0, 0, 0);
while (d.getDate() > 1) {
maxday++;
d = new Date(year.value, month.value - 1, maxday, 0, 0, 0, 0);
}
maxday--;
}
var day = document.getElementById('day');
while (minday <= maxday) {
opt = document.createElement('option');
opt.value = minday;
opt.innerHTML = minday;
day.appendChild(opt);
minday++;
}
}
function update_dates() {
var now = new Date();
var newest = [];
newest[0] = now.getFullYear();
newest[1] = now.getMonth() + 1;
newest[2] = now.getDate();
var old = new Date(now.getTime() - 1095 * 86400 * 1000);
var oldest = [];
oldest[0] = old.getFullYear();
oldest[1] = old.getMonth() + 1;
oldest[2] = old.getDate();
//selected date in selectboxes
var year = document.getElementById('year');
var month = document.getElementById('month');
var day = document.getElementById('day');
var sel = new Date(year.value, month.value-1, day.value, 0,0,0,0);
var selected = [];
selected[0] = sel.getFullYear();
selected[1] = sel.getMonth() + 1;
selected[2] = sel.getDate();
year.innerHTML = month.innerHTML = day.innerHTML = ''; //clear old list
// YEARS
var opt;
var i = oldest[0];
while (i <= newest[0]) {
opt = document.createElement('option');
opt.value = i;
opt.innerHTML = i;
if (i == selected[0]) {
opt.selected = 'selected';
}
year.appendChild(opt);
i++;
}
// MONTHS
var minmonth = (year.value == oldest[0]) ? oldest[1] : 1;
var maxmonth = (year.value == newest[0]) ? newest[1] : 12;
while (minmonth <= maxmonth) {
opt = document.createElement('option');
opt.value = minmonth;
opt.innerHTML = minmonth;
if (minmonth== selected[1]) {
opt.selected = 'selected';
}
month.appendChild(opt);
minmonth++;
}
// DAYS
var minday = (year.value == oldest[0] && month.value == oldest[1]) ? oldest[2] : 1;
var maxday = (year.value == newest[0] && month.value == newest[1]) ? newest[2] : 33;
if (maxday == 33) {
// find correct maxday
maxday = 27;
var d = new Date(year.value, month.value - 1, maxday, 0, 0, 0, 0);
while (d.getDate() > 1) {
maxday++;
d = new Date(year.value, month.value - 1, maxday, 0, 0, 0, 0);
}
maxday--;
}
while (minday <= maxday) {
opt = document.createElement('option');
opt.value = minday;
opt.innerHTML = minday;
day.appendChild(opt);
if (minday == selected[2]) {
opt.selected = 'selected';
}
minday++;
}
}