I need help with the following question

Write a script based on the program in Exercise 11.13 that inputs several lines of text and
uses String method indexOf to determine the total number of occurrences of each letter of the
alphabet in the text. Uppercase and lowercase letters should be counted together. Store the totals for
each letter in an array, and print the values in tabular format in an HTML5 textarea after the totals
have been determined.

I need this wirtten in javascript

please help

thanks