What/How kind/much data are you trying to send the client-side?
You can easily use attributes to make strings of data available on the client-side. I.e:
PHP Code:
function onCreated() {
this.attr[2] = "Hello world!";
}
//#CLIENTSIDE
function onPlayerEnters() {
this.chat = this.attr[2]; // NPC will chat "Hello World!"
}
You may encounter issues if your setting data that is longer than 200 characters, but that's still a fair chunk available and there's still 30 (or 31?) attributes available.
If you need something more complicated you'll need to triggerclient to a weapon, and set it in the NPC.