Checking input response by keypress #/key position in string VAR

Hi all,

I'm not sure why I'm not able to find this information, but I'm sure it's my query -- If this has been asked, just redirect me ;)

I'm trying to create input which tests keystrokes and compares them to a "response" variable (string). Once the user presses a key that doesn't "match," it immediately kicks them out of the interaction.

Example:

required response: Lectora

If the user types: Leck -- they are now kicked out of the loop (the K should be a T)

Here's what I'm currently capturing:

-- how many numbers of keys have been pressed (probably not necessary for this since i should be able to pull from the INPUT data)

-- entries into the form input box

-- variable contents (correct response)

Is there a way to do something like:

//capture recent key pressed and position in the array combo

(so input Leck would be something like [Input_001 1, L 2, E 3, C 4, K ]...)

//compare the array with a response key combination/position key combo in another variable

response required: lectora

1, L (ok)

2, E (ok)

3, C (ok)

4, K (uh oh!)

This shouldn't be that hard -- I'm just not sure how to call location of a string within a variable. Can something like

if ThisKeyPressed == (VAR(theCorrectResponse), 4) be used? (checking the most recent key pressed and comparing it with the 4th place in the theCorrectResponse variable).

What I can't seem to figure out is how to compare the two with each keypress in a way that doesn't require a gazillion interactions (we've all done those workarounds ;) )

Thanks in advance for any direction you can provide.

Lisa