使用JavaScript根据星期几更改消息？

Question

I am adding functionality to a website to change the message depending on if a food truck is open. I was successfully able to make the message change depending on the time, but I'm having trouble implementing getDay() to show the closed message all day on Saturday and Sunday.

Here is the working script that I have so far:

 <script language="JavaScript">
        var mess1="";
        var outmess= "Kendo's Cuisine "
        document.write("<center><font size=+1><i><b>")
        day = new Date( )
        hr = day.getHours( )
        if (( hr >= 0 ) && (hr <= 11 ))
        mess1= "is closed right now. He's open Mon - Fri 11am - 2pm. "
        if (( hr >= 11 ) && (hr < 13))
        mess1=" is open right now! Call in your order to have it ready by the time you get here!"
        if (( hr >= 13) && (hr <= 14))
        mess1= "usually runs out of food by now! Call before you come!"
        if (( hr >= 14 ) && (hr <= 24 ))
        mess1= "is closed right now. He's open Mon - Fri 11am - 2pm. "
        document.write("<blink>")
        document.write(outmess)
        document.write("</blink>")
        document.write(mess1)
        document.write("</b></i></font></center>")
      </script>

Answer 1

It seems you want to put up a "closed" message outside the hours of 11:00 to 14:00 Monday to Friday, so perhaps:

function isOpen(date) {
  var day = date.getDay();
  var hour = date.getHours();

  if (day == 0 || day == 6 || hour < 11 || hour > 13) {
    // shop is closed
    return false;
  }

  // Otherwise, the shop is open
  return true;
}

Note however that if the date object is created on the client, it will be local to that timezone, which may not match wherever the shop is. So you probably need to do this based on UTC time, which will be consistent everywhere.

Answer 2

Use getDay() method to get the weekday from date object. It returns a number from 0 - 6 to indicate days from sunday - saturday.

So you have to check like

var day = new Date();
if(day.getDay() == 0 || day.getDay() == 6) {
   alert("shop is closed");
}