Create the countdown$()$ function and within the function add the following:

Declare the secsString variable by calling the addLeadingZero$()$ function using the secsLeftvariable as the function value. The addLeadingZero$()$function is used to add leading zeroes to numeric values from $0$ to $9.$

Change the text content of the document element with the ID seconds to the value of the secsString variable.

Run the checkCountdown$()$ function to determine whether the end of the countdown has been reached.

Use the decrement operator to reduce the value of the secsLeft variable by $1.$