Question

拔出我的头发试图解决这个问题。我想通过innerHTML根据星期几显示一条消息。我在这里和其他地方看过无数类似的问题，但似乎没有任何工作。我已经尝试过if语句的各种更改，但没有任何成功。我尝试的所有内容都会返回“未定义日期”错误。

提前致谢。

（另外，可能相关：我是Javascript的新手）

JS：

print('Mine: ', timeit.timeit(stmt=stAditya, number=1000000)) # 5.524377981713729
print('Jatimir:', timeit.timeit(stmt=stTwo, number=1000000)) # 6.971933613624651
print('Kasramvd:', timeit.timeit(stmt=oth, number=1000000)) # 15.090121147017014

Answer 1

day是startTime函数的局部变量。它在该功能之外不可用，并且您尝试在if (day == "Fri")中访问它。在startTime()内移动if-else语句，它应该有效。

Answer 2

问题在于day变量。它是在startTime函数内声明的，因此无法在if语句

中访问它

＆＃13;

var day = '';

function checkTime(i) {
  if (i < 10) {
    i = "0" + i;
  }
  return i;
}

function startTime() {
  var today = new Date();
  var weekday = new Array(7);
  weekday[0] = "Sun";
  weekday[1] = "Mon";
  weekday[2] = "Tues";
  weekday[3] = "Weds";
  weekday[4] = "Thurs";
  weekday[5] = "Fri";
  weekday[6] = "Sat";
  day = weekday[today.getDay()];
  var h = today.getHours();
  var m = today.getMinutes();
  var s = today.getSeconds();
  var month = new Array(12);
  month[0] = "Jan";
  month[1] = "Feb";
  month[2] = "March";
  month[3] = "April";
  month[4] = "May";
  month[5] = "June";
  month[6] = "July";
  month[7] = "Aug";
  month[8] = "Sept";
  month[9] = "Oct";
  month[10] = "Nov";
  month[11] = "Dec";
  var currentMonth = month[today.getMonth()];
  var year = today.getFullYear();
  // add a zero in front of numbers<10
  h = checkTime(h);
  m = checkTime(m);
  s = checkTime(s);
  document.getElementById('currentTime').innerHTML = day + " " + h + ":" + m + ":" + s;
  t = setTimeout(function() {
    startTime()
  }, 500);
}
startTime();
if (day == "Fri") {
  document.getElementById("timeText").innerHTML = "Nearly the weekend!";
} else if (day == "Sat") {
  document.getElementById("timeText").innerHTML = "It's Beer O'Clock";
} else {
  document.getElementById("timeText").innerHTML = "JS Failed";
}

＆＃13;

<div id="currentTime"></div>
<div id="timeText"></div>

＆＃13;

Answer 3

为我做了一些调整

＆＃13;

function checkTime(i) {
  if (i < 10) {
    i = "0" + i;
  }
  return i;
}
function startTime() {
  var today = new Date();
  var weekday = new Array(7);
  weekday[0] = "Sun";
  weekday[1] = "Mon";
  weekday[2] = "Tues";
  weekday[3] = "Weds";
  weekday[4] = "Thurs";
  weekday[5] = "Fri";
  weekday[6] = "Sat";
  var day = weekday[today.getDay()];
  var h = today.getHours();
  var m = today.getMinutes();
  var s = today.getSeconds();
  var month = new Array(12);
	month[0] = "Jan";
	month[1] = "Feb";
	month[2] = "March";
	month[3] = "April";
	month[4] = "May";
	month[5] = "June";
	month[6] = "July";
	month[7] = "Aug";
	month[8] = "Sept";
	month[9] = "Oct";
	month[10] = "Nov";
	month[11] = "Dec";
	var currentMonth = month[today.getMonth()];
  var year = today.getFullYear();	
  // add a zero in front of numbers<10
  h = checkTime(h);
  m = checkTime(m);
  s = checkTime(s);	
  document.getElementById('currentTime').innerHTML = day + " " + h + ":" + m + ":" + s;	
  
  if (day == "Fri") {
	document.getElementById("timeText").innerHTML = "Nearly the weekend!";
} else if (day == "Sat") {
	document.getElementById("timeText").innerHTML = "It's Beer O'Clock";
} else {
	document.getElementById("timeText").innerHTML = "JS Failed";
}
}
startTime();

＆＃13;

<div id="currentTime"></div>
<div id="timeText"></div>

＆＃13;

JS：根据星期几显示消息

3 个答案: