help me with javascript code

below is html

below is javascript

need help with the red circled part

this is instruction.

1. In script.js, write the fahrenheitToCelsius function where indicated. The fahrenheitToCelsius function should have one parameter named fahrenheit, representing a Fahrenheit temperature. If fahrenheit is a finite number, your function should return that temperature converted to Celsius. If fahrenheit is not a finite number, your function should do nothing (the value undefined will be automatically returned).
2. In script.js, notice the event handler that runs when the user clicks the button with id equal to calc-celsius-temp; it reads the input as a number and calls your fahrenheitToCelsius function to store the converted temperature in the outputNumber variable. Finish it by writing one line of code where indicated in the event handler. It should output the variable outputNumber to the element with id equal to celsius-output with exactly two (2) digits after the decimal point.

Fahrenheit:

°C

L