Particles with lifespan

HTML

<html>
<head>
<title>Canvas</title>
<script type="text/javascript">
// When the window has loaded, DOM is ready. Run the draw() function.

</script>
</head>
<body>
  <canvas id="myCanvas" width="100vw" height="100vh"></canvas>
</body>
</html>

CSS

#myCanvas{
    background:black;
}
body{
    overflow:hidden;
}

JavaScript

// Create an array to store our particles
var particles = [];

// The amount of particles to render
var particleCount = 360;

// The maximum velocity in each direction
var maxVelocity = 1.5;

// The target frames per second (how often do we want to update / redraw the scene)
var targetFPS = 60;

// Set the dimensions of the canvas as variables so they can be used.
var canvasWidth;
var canvasHeight;
function updateBounds(){
    canvasHeight = $(window).height();
    canvasWidth = $(window).width();

    $('#myCanvas').attr("height", $(window).height());
    $('#myCanvas').attr("width", $(window).width());
    
}
$(window).resize(updateBounds);
updateBounds();

var arcOptim = 2 * Math.PI;

// A function to create a particle object.
function Particle(context) {

    // Set the initial x and y positions
    this.x = 0;
    this.y = 0;

    // Set the initial velocity
    this.xVelocity = 0;
    this.yVelocity = 0;

    // Set the radius
    this.radius = 20;

    // Store the context which will be used to draw the particle
    this.context = context;
    
    // The function to draw the particle on the canvas.
    this.draw = function() {
        if(!this.isAlive){
            return;
        }
        
        var multiplier = (this.lifeRemaining / 100);
        var size = this.radius * multiplier ;
                
        // Draw the circle as before, with the addition of using the position and the radius from this object.
        this.context.beginPath();
        this.context.arc(this.x, this.y, size, 0, arcOptim, false);
        this.context.fillStyle = this.color;
        this.context.fill();
        this.context.closePath();
    };

    // Update the particle.
    this.update = function() {
        
        --this.lifeRemaining;
        if(this.lifeRemaining<=0){
            this.isAlive = false;
        }
        
        if(!this.isAlive){
            this.init();
            return;
        }
        
        // Update the position of the particle with the...