可能是一个简单的修复，但不能修复自己

Question

anyone know what I'm doing wrong with this, id like to make a welcome message that displays on startup which asks you your name and then welcomes you with a greeting dependent on the current time.

The issue I'm having is that the prompt will work if everything else is comment blocked but also won't display on to the page in white text

    var name
    name = prompt("Please enter your name.");

    document.getElementById("demo").innerHTML = (msg);
    msg.style.color = 'White';

    var now = Date();
    var hrs = now.getHours();
    var msg = "";

    if (hrs >  6) msg = "Good morning";   
    if (hrs > 12) msg = "Good afternoon";   
    if (hrs > 17) msg = "Good evening"; 

Answer 1

1. you used msg before its declared
2. msg don't have style property as it's not an element
3. you never used name
4. you used white color, which is same as default page background color
5. you assigned value to innerHTML before its assigned to msg variable
6. date object should be created with new keyword var now = new Date();

var name = prompt("Please enter your name."); 
var msg = "";
console.log(name);
 document.getElementById("demo").style.color = 'red'; // use other color because white is default background color and your text will not be visible
var now =  new Date(); 
var hrs = now.getHours(); 
console.log(hrs);
if (hrs > 0) 
  msg = "Good early morning "+ name; 
else if (hrs > 6) 
  msg = "Good morning "+ name; 
else if (hrs > 12) 
  msg = "Good afternoon "+ name; 
else if (hrs > 17) 
  msg = "Good evening "+ name; 
console.log(msg);
document.getElementById("demo").innerHTML = msg;