I am trying to use the Popup Messages plugin with this plugin so when a player connects it will bring up a message on the screen which they have to read (because it is amazing how many people don't bother reading the standard Connect Message which comes up in the chat window).

Because the Popup Messages plugin requires that the message and player name is inside inverted commas it doesn't seem to work, because Connection Commands also requires that the command is inside inverted commas. Both the sets of inverted commas end up nested inside one-another. What I have tried is something like this:

"Commands on connection": [
    "popupmsg.toplayer "this is a test message" "{name}""
  ],​

Which of course won't work because it hits the second inverted commas and thinks thats the end of the statement. So I tried this:

"Commands on connection": [
    "popupmsg.toplayer 'this is a test message' '{name}'"
  ],​

with a single inverted comma nested in the double inverted commas, but no go either. Ok so I tried something like this?

"Commands on connection": [
    "popupmsg.toplayer \"this is a test message\" {name}"
  ],

but yeah this didn't work either. I'm obviously not too good at this kind of thing.
Any help with this would be greatly appreciated!
Thanks in advance.

You'd have to escape them with \, that's how JSON works; so your last example would be right.

Ok thanks, but the name also needs to be in inverted commas, so the correct implementation would be this??

"Commands on connection": [
    "popupmsg.toplayer \"this is a test message\" \"{name}\""
  ],​

or does {name} already put it in inverted commas?