Tyranobuilder Snow Effect

particles.ks

;============================================================
; Particles - Snow
;============================================================

*init_particles
[html name='part_layer']
<script>
$(".layer_free").css({
    "z-index":29
})
</script>
<canvas id="part_canvas"></canvas>
[endhtml]

[iscript]
 tf.part_speed=1;
[endscript]

[macro name="snow"]
[iscript]
(function() {
    var requestAnimationFrame = window.requestAnimationFrame 
    || window.mozRequestAnimationFrame 
    || window.webkitRequestAnimationFrame 
    || window.msRequestAnimationFrame ||
    function(callback) {
        window.setTimeout(callback, 1000 / 60);
    };
    window.requestAnimationFrame = requestAnimationFrame;
})();
var canvas = document.getElementById("part_canvas");
var ctx = canvas.getContext("2d");
var W = window.innerWidth;
var H = window.innerHeight;
canvas.width = W;
canvas.height = H;
var angle = 0;
var numParticles = 500;
var particles = [];

for (var i = 0; i < numParticles; i++) {
  particles.push({
    x: Math.random()*W,
    y: Math.random()*H,
    radius: Math.random()*4+1,
    d:Math.random()*numParticles
  })
}

function drawParticles() {
  ctx.clearRect(0, 0, W, H);
  ctx.fillStyle = "rgba(255, 255, 255, "+0.8+"";
  ctx.beginPath();
  for (var i = 0; i < numParticles; i++) {
    var f = particles[i];
    ctx.moveTo(f.x, f.y);
    ctx.arc(f.x, f.y, f.radius, 0, Math.PI*2, true);
  }
  ctx.fill();
  moveParticles();
}

function moveParticles() {
  angle +=0.01
  for (var i = 0; i < numParticles; i++) {
    var f = particles[i];
    f.y += Math.cos(angle+f.d) + 1 + f.radius/2 * tf.part_speed;
    f.x += Math.sin(angle);
    if (f.x > W+5 || f.x < -5 || f.y > H) {
      if (i%3 > 0) {
        particles[i] = {x: Math.random()*W, y: -10, radius: f.radius,d:f.d};
      } else {
        if (Math.sin(angle) > 0) {
          particles[i] = {x: -5, y: Math.random()*H, radius: f.radius,d:f.d};
        } else {
          particles[i] = {x: W+5, y: Math.random()*H, radius: f.radius,d:f.d};
        }
      }
    }
  }
}

function init() {
  canvas.style.webkitFilter = "blur(0.75px)";
  drawParticles();
}
setInterval(init, 30);
[endscript]
[endmacro]

;remove particles layer
[macro name="remove_particles"]
[anim name='part_layer' opacity=0]
[wt]
[iscript]
$("#canvas").remove();
$(".part_layer").remove();
[endscript]
[endmacro]

hi! delacannon! i wonder if u answer this question..im learning.

1. line 96-> where does #canvas come from? should it be not #part_canvas according to the [html] definition?
2. line 97 -> .part_layer is from [html name='part_layer']?

thx in advance!
ps. im working on minigame in tyranobuilder. it seems hard to destroy the minigame and the html layer and get out naturally.