Design and implement a Web page named pal.html that tests whether a word or phrase is a palindrome. Your page should allow the user to enter a word or phrase and then display a string indicating whether that word or phrase is a palindrome. The code that evaluates the user's input should be case insensitive and should ignore any non-letters within the string. Thus, the following words and phrases would all be considered palindromes:
Bob
Able was I ere I saw Elba.
A man; a plan; a canal; Panama!
The choice of page elements (e.g., test boxes, buttons, text areas) and their layout is up to you, but the overall design should be intuitive and user friendly.