All you need
Flour, eggs, coconut milk, salt, and just a little ground turmeric (mostly for color).
After you sift the flour and turmeric powder together, whisk them with the remaining ingredients until a smooth, thin batter forms. Then strain the batter into a clean bowl; it's essential that it doesn't have any lumps, as the shape it takes on the pan is quite delicate and any imperfections will be visible.
Let it be
Cover and let rest for 30 minutes.
In Melaka or Kuala Lumpur, it's easy to find specialized roti jala gear, namely, this mold and this cooking surface. However, just about any flat, heated surface would work to cook on (a griddle or even a large nonstick pan). As for the batter drizzler, I'd think a plastic cup with a few punched holes would do you fine; squeeze bottles and quick hands might be an even better option. Really, you just need anything that can give you more-or-less even streams of batter.
Oil the surface
A light brush of oil between every roti will keep things from sticking.
Fill the cup
Ladle the batter into your pouring implement.
Working quickly, hold the mold over the heated surface and make a series of circles, moving your way around the pan, to form the netlike pattern.
Keep it low
Hold the drizzler low to the pan, or you'll end up with a pattern of spatters rather than neat, tight spirals.
Once you've drizzled your way around the edges (this should only take about 4 or 5 seconds), add one more swirl to the middle, and stop.
These thin, delicate pancakes cook quickly; run a spatula under the edges to check if they're done after about 45 or 60 seconds. (They're so thin that they don't need to be flipped.) If they lift easily and there's a bit of a golden hue on the bottom, they're ready.
Flip and roll
Flip the pancake over onto a plate (you want the side that didn't touch the heated surface to face down). Then either fold both edges into the middle, and roll up in a spiral...
... or fold in half, then fold that half-circle into thirds, to form a loose wedge.
"Jala" means net; pretty apt.
While I'd happily nibble roti jala on its own, it's always served with a curry for dipping (here, a chicken curry). Its holes and crevasses are perfect for picking up thick sauces, giving you maximum surface area for curry-clinging.