[javascript] I want the value to be blank when you press the Clear button.

There are windows 1 and 2.

If you press any button in window 1, window 2 appears. Window 1 contains a value of a. In window 2, you can change the value of a to another value (double-click or press enter as a list type) However, Window 2 does not have the 'Clear' function to return the value of a to blank.

How do I create this erase function? Please let me know...