A counter that adds... and subtracts?
Hi all - this seems like it should be an easy feature, but apparently my brain can't handle variables right now, so I'm looking for some help.
I'd like to create a simple on-screen counter using checkboxes. Basically: have you used the tool listed on the screen? Yes or No. If they click "Used It", then the counter increases by one and they go to the next screen and then asked if they've used another tool. The counter will keep a running total. (I've gotten it to work this far)
Here is my sticking point: If they *accidentally* check "Used It" and then click it again to uncheck it, right now the variable on the checkbox continues to add 1 to the counter (ie: click "Used It" once and you get a running score of "1"... then change your mind and click the "Used It" box to uncheck it, your score goes up to "2" when it should now be equal to "0"). I can't seem to figure out how to add a second condition/variable that will subtract 1 if you click the same checkbox a second time. Suggestions?