Question

/* complete javascript file according to the individual instructions
given in the comments. */

// 1) Prompt the user to enter their first name. 
// Display an alert with a personal greeting for the user 
// with their first name (example: Hello, Dave!)



// 2) Create a Try code block that will cause a ReferenceError.  
// Create a Catch code block that will display the error in the  
// console with console.error() 



// 3) Prompt the user to enter a number. If the user input is 
// not a number, throw a custom error to the console and alert 
// the user. 



// Solving a Problem!
// 4) Create a function named productOf() that accepts 
// two numbers as parameters: productOf(num1,num2)
// Create a Try block in the function that checks to see if 
// num1 and num2 are numbers.
// If both parameters are numbers, return the product of 
// the two numbers: num1 * num2
// If either num1 or num2 are not numbers, throw a custom 
// error to the console and alert the user.
// After defining the function, ask the user to enter a number. 
// Then ask the user to enter a second number.
// Call the function with the values entered by the user.



// Solving a Problem!
// 5) Create a loop that counts from 1 to 20. 
// If the current number is even, add it to this empty array:
var myArray = [];
// If the current number is odd, log an odd number warning to 
// the console.
// However, if the number equals 19, set a debug breakpoint.
// After the loop completes, print the array to the console.

Answer 1

//1
var an=prompt("Enter your first name!");
alert("Hello, "+an+"!");

//2
try{
   add();
}
catch(e){
   console.error("Function is not defined!");
}

//3
function notAnumber(){
   throw new Error('Entered value is not a number!'); // Function notAnumber throws an error
}
   var num=prompt("Enter a number:");
   if(isNaN(num)) {
       alert("Entered value is not a number!");
       console.error(notAnumber());  
   }
   else {
       alert("Entered number is : "+num);
   }

//4
function notAnumber(){
   throw new Error('Entered value is not a number!'); // Function notAnumber throws an error
}
function productOf(num1,num2) {
   flag=0
   try {
       if(isNaN(num1) || isNaN(num2)) {
           flag=1;
           alert("Entered value is not a number!");
       }
       else {
           return num1*num2;
       }
   }
   catch(e) {
      
   }
   if(flag==1){
       console.error(notAnumber());
      
   }
}

var n1=prompt("Enter first number:");
var n2=prompt("Enter second number:");
alert(productOf(n1,n2));

//5
var myarray=[]
var j=0
for(i=1;i<=20;i++){
   if(i%2==0){
       myarray[j]=i;
       j+=1;
   }
   else if(i==19){
       debugger;
   }
   else{
       console.log(i+" number is odd");
   }
}

console.log(myarray)