In JavaScript, join and pop are two methods that can be used on arrays.
join method is used to concatenate all the elements of an array into a string. pop method is used to remove the last element of an array and return that element. It modifies the original array, reducing its length by one.
<!DOCTYPE html>
<html>
<head>
<!-- <script src="main.js"></script> -->
</head>
<body>
<script>
var old_pl = new Array("Cobol", "Fortran", "Algol");
var new_string = old_pl.join(" ");
document.write(new_string);
</script>
</body>
</html>
This script creates an array called old_pl with three elements: "Cobol", "Fortran", and "Algol". Then, the join method is called on the old_pl array with a space as the separator argument. The resulting string is assigned to a variable called new_string.
Finally, the document.write method is used to output the new_string to the webpage. The resulting output would be a string that concatenates all the elements of the old_pl array.
<!DOCTYPE html>
<html>
<head>
<!-- <script src="main.js"></script> -->
</head>
<body>
<script>
var old_pl = new Array("Cobol", "Fortran", "Algol");
document.write(old_pl + "<br><br>");
old_pl.pop();
document.write(old_pl + "<br><br>");
old_pl.pop();
document.write(old_pl + "<br><br>");
old_pl.pop();
</script>
</body>
</html>
This script creates an array called old_pl with three elements: "Cobol", "Fortran", and "Algol". Then, the document.write method is used to output the old_pl array to the webpage.
After that, the pop method is called on the old_pl array three times in a row, which removes the last element of the array on each call.
After each pop method call, the document.write method is used to output the old_pl array to the webpage again. As a result, the output of the script would be:
Cobol,Fortran,Algol
Cobol,Fortran
Cobol
The first line shows the original array with all three elements. The second line shows the old_pl array after the first pop method call, which removed the last element ("Algol") from the array. The third line shows the old_pl array after the second pop method call, which removed the last element ("Fortran") from the array. The fourth line shows the old_pl array after the third pop method call, which removed the last element ("Cobol") from the array.
At this point, the old_pl array is empty.
