编写一个JavaScript js程序
程序接收三个输入,分别作为年份,月份,和日期,要求年份在2000到2018之间,要求输出这个日期属于该年的第几天，如 输入年份，2018，输入月份 2，输入日期 3，则页面上输出，该日期是2018年的第34天
按照你的要求编写的输出日期属于该年的第几天的Javascript程序如下
<html><head>
<script type=text/javascript>
function check(){
var year=parseInt(document.getElementById("year").value);
var month=parseInt(document.getElementById("month").value);
var day=parseInt(document.getElementById("day").value);
if(year<2000 || year>2018){
alert("输入年份要求在2000到2018之间");
var t = document.getElementById("year");
t.focus();
return false;
}
var days=0;
for(var i=1;i<month;i++){
switch(i){
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12:days=days+31;break;
case 4:
case 6:
case 9:
case 11:days=days+30;break;
case 2:
if(year%4==0&&year%100!=0||year%400==0)
days=days+29;
else
days=days+28;
break;
}
}
days=days+day;
document.getElementById("result").innerHTML="该日期是"+year+"年的第"+days+"天";
}
</script>
</head>
<body>
年份<input type="text" name="year" id="year" value=""><br>
月份<input type="text" name="month" id="month" value=""><br>
日期<input type="text" name="day" id="day" value=""><br>
<input type="button" value="确定" onclick="check();"><br>
<div id="result"></div>
</body>
</html>
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第1个回答 2018-09-15
请采纳，谢谢！
<!DOCTYPE html><html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>根据年月日判断属于当年的第几天</title>
</head>
<body>
<select name="year" id="year">
<option value="2000">2000</option>
<option value="2001">2001</option>
<option value="2002">2002</option>
<option value="2003">2003</option>
<option value="2004">2004</option>
<option value="2005">2005</option>
<option value="2006">2006</option>
<option value="2007">2007</option>
<option value="2008">2008</option>
<option value="2009">2009</option>
<option value="2010">2010</option>
<option value="2011">2011</option>
<option value="2012">2012</option>
<option value="2013">2013</option>
<option value="2014">2014</option>
<option value="2015">2015</option>
<option value="2016">2016</option>
<option value="2017">2017</option>
<option value="2018">2018</option>
</select>
<select name="mongth" id="month">
<option value="1">1月</option>
<option value="2">2月</option>
<option value="3">3月</option>
<option value="4">4月</option>
<option value="5">5月</option>
<option value="6">6月</option>
<option value="7">7月</option>
<option value="8">8月</option>
<option value="9">9月</option>
<option value="10">10月</option>
<option value="11">11月</option>
<option value="12">12月</option>
</select>
<select name="day" id="day"></select>
<div id="result"></div>
<script>
var yearSel = document.getElementById('year');
var monthSel = document.getElementById('month');
var daySel = document.getElementById('day');
var resultElm = document.getElementById('result');
// 判断是否是闰年
function isLeapYear(n) {
return ((n % 4 == 0 && n % 100 != 0) || n % 400 == 0);
}
function calculate(year, month, day) {
var num = new Date(year+'/' + month + '/'+ day +' 24:0:0').getTime() - new Date(year+'/1/1 0:0:0').getTime();
num = num/24/3600/1000;
resultElm.innerHTML = '今天是'+year+'年第'+num+'天';
}
// 设置天数下拉框
function setDaySelOptions(year, month) {
var html = '';
var max;
switch (month) {
case 1:
case 3:
case 5:
case 7:
case 8:
case 10:
case 12: max=31;break;
case 4:
case 6:
case 9:
case 11: max=30;break;
case 2:
if (isLeapYear()) {
max = 29;
} else {
max = 28;
}
break;
}
for (var i=0;i<max;i++) {
html+='<option value="'+(i+1)+'">'+(i+1)+'</option>'
}
daySel.innerHTML = html;
}
// 初始化
setDaySelOptions(+yearSel.value, +monthSel.value);
calculate(+yearSel.value, +monthSel.value, +daySel.value);
yearSel.onchange = function() {
var year = parseInt(yearSel.value);
var month = parseInt(monthSel.value);
setDaySelOptions(year, month);
var day = parseInt(daySel.value);
calculate(year, month, day);
}
monthSel.onchange = function() {
var year = parseInt(yearSel.value);
var month = parseInt(monthSel.value);
setDaySelOptions(year, month);
var day = parseInt(daySel.value);
calculate(year, month, day);
}
daySel.onchange = function() {
var year = parseInt(yearSel.value);
var month = parseInt(monthSel.value);
var day = parseInt(daySel.value);
calculate(year, month, day);
}
</script>
</body>
</html>
第2个回答 2018-09-15
<script>
function get_days(year,month,day){
var datatime=year+"/"+month+"/"+day+" 24:0:0";
var date=new Date(datatime).getTime()-new Date(year+"/1/1 0:0:0").getTime();
date=date/24/3600/1000;
var text="该日期是"+year+"年的第"+date+"天";
return text;
}
alert(get_days(2018,2,3));
</script>
function get_days(year,month,day){
var datatime=year+"/"+month+"/"+day+" 24:0:0";
var date=new Date(datatime).getTime()-new Date(year+"/1/1 0:0:0").getTime();
date=date/24/3600/1000;
var text="该日期是"+year+"年的第"+date+"天";
return text;
}
alert(get_days(2018,2,3));
</script>