Separating digits of a number in JavaScript

We are required to write a JavaScript program that provides user with a input. When the user inputs some value and press the button, our function should check if the input is a valid number,if it is a valid number, the program should print all digits of the number separately to the screen.

For example ? If the input is ?

43354

Then the output on the screen should be ?

4
3
3
5
4

Let us write the code for this function ?

The code for this will be ?

HTML

   
      
      
      
   

   

      

          Enter number 
         
         
 
      

JS

function perform() {
   var outputObj = document.getElementById("output");
   var a = parseInt(prompt("Please enter a number: ", ""));
   var digit = "";
   outputObj.innerHTML = ""
   while(a > 0){
      let num = a%10
      a = Math.floor(a/10)
      digit += "
"+num+"
"
   }
   outputObj.innerHTML = digit;
   document.getElementsByTagName("button")[0].setAttribute("disabled","true");
}

And the output on the screen will be ?

After clicking OK button,