Write a script that allows a user to enter a numeric grade and then determine the letter grade. Use a PHP document and a HTML document containing a form with 5 text boxes to enter the numeric grades. Print a message to the user stating whether or not the grade is valid (remember the numeric grade can only be between 0 100), and the letter grade for each numeric grade entered. Use the grade determination criteria from the syllabus. Example if a grade between 90 93 is entered, a letter of A- will display to the screen. If only 4 grades were entered, then only 4 letter grades should be listed to the screen. Be sure to check that 0 displays an F.