The neon effect with javascript P5 JavaScript library.

The P5.js is a JavaScript library for creative coding.
You can use by adding this link on your HTML area using the script tag:

https://cdnjs.cloudflare.com/ajax/libs/p5.js/0.9.0/p5.min.js

You can use it like any JavaScript library.
You have two functions: setup and a draw for setup and drawing.

function setup() {
  createCanvas(window.innerWidth, window.innerHeight);
}

function draw() {
  ellipse(50, 50, 80, 80);
}

Then you can fill these functions with any javascript code.
You can see a neon effect with two bezier functions.
The example uses the mouse movement to change the bezier lines.
You can see many examples created by me at codepen website.

Using p5.js to create a progressbar .

This is an old tutorial about how to create a progressbar with processing.
To convert to p5.js you need to change the processing source code to javascript.
You can read about this conversion here.
In my example I change all variable types to var and I remove the frame.setTitle.
If you using the processing I.D.E. then you need to change from the right area from java to p5.js.
This will make a index.html file ( don't change this file).
This is the source code for p5.js and is working well:

// example progressbar 
// default variables for progressbar
// start the time for progressbar
var startTime; 
// counter progressbar 
var counter;
// maximum time progressbar
var maxTime; 
// boolean for the end progressbar 
var done; 
// settings for this example
function setup() { 
// set title of window
//frame.setTitle("Example progressbar | free-tutorials.org");
// window size and background color
// p5.js
createCanvas(640,130);
 
//size(640,130);
background(25); 
// set variables of progressbar
counter = 0; 
startTime= millis(); 
maxTime=int(random(1000,1976)); 
done=false; 
//end settings
} 
// draw all text and progressbar
function draw() { 
  // set same background color
  background(255); 
 
  // check end of progressbar fill
  if (counter-startTime < maxTime) {
  counter=millis();
  }  else { done=true;  }
  // create the color for fill progressbar
  fill(110,110,255);
  // no stroke for draw
  noStroke();
  // show all text variables and progressbar
  text("Progress bar blue - size 620", 230, 20); 
  rect(10,30,map(counter-startTime,0,maxTime,0,620), 30 );
  text("counter- startTime "+int(counter- startTime)+" ",10,80);
  text("maxTime "+ int(maxTime) +  " ", 10,100);
  text("map converted counter-startTime"+ int ( map(counter-startTime,0,maxTime,0,200)), 10,120);
  noFill();
 
  }
// reload the draw of progress bar 
function mousePressed () { 
  if (done) { counter = 0; startTime= millis();
  maxTime=int(random(1000,1976)); 
  done=false;
  }
}