[Tigairius]

Not sure what you're asking.
If you only want it to display the first 15 characters then you can do: params[1].substring(0, 15)

if you want to cut off the first 15 characters you can do: params[1].substring(15)

If you want to cut off all the characters before "15" you can do:
params[1].substring(params[1].pos(15))

Also you should use == for comparison. Using one = is for declaration.
if (player.rupees == params[1].substring(15)) { for example.

If you just need to parse a string you could do:
params = obj.text.tokenize();

then use params[0] for the first space. You can define which character to parse like this:
params = obj.text.tokenize("a");
if obj.text = "123abc123abc";
params[0] would = 123
params[1] would = bc123
and so on.