'this' is only the generic form of the variable, display. In earlier code in my calculator, I declared display as a variable: var display = 0;
Display is initially set as 0 so the calculator starts with a blank screen.
There are actually two variables in this calculator which I have declared: display and total. Both are declared in my code before the actual code I posted.
var display = 0;
var total = 0;
When the user enters a number, this.display (the generic form) is assigned the value of that number. When an operand is hit (+, -, / ...), total is assigned the current value of display, and then display is reset to 0.
Thank you very much for your help!