macOS Sierra: HTML5 & JavaScript: Pong

Command:

$ cat html5game.html


Result:

<canvas id="gc" width="640" height="480"></canvas>
<script>
p1y=p2y=40; //Paddle vertical positions
pt=10; //Paddle thickness
ph=100; //Paddle height
bx=by=50; //Ball position
xv=yv=4; //Velocities
bd=6; //Ball dimension
score1=score2=0;
ais=2; //AI Speed
window.onload=function() {
c=document.getElementById('gc');
cc=c.getContext('2d');
setInterval(update,1000/30); //30 times a second
c.addEventListener('mousemove',function(e){
p1y=e.clientY-ph/2;
});
}
function reset(){
bx=c.width/2;
by=c.height/2;
xv=-xv;
yv=4;
}
function update(){
bx+=xv;
by+=yv;
if(by<0 && yv<0)
{
yv=-yv;
}
if(by>c.height && yv>0)
{
yv=-yv;
}
if(bx<0)
{
if(by>p1y && by<p1y+ph){
xv=-xv;
dy=by-(p1y+ph/2);
yv= dy*0.3;
} else {
score2++;
reset();
}
}
if(bx>c.width)
{
if(by>p2y && by<p2y+ph){
xv=-xv;
dy=by-(p2y+ph/2);
yv= dy*0.3;
} else {
score1++;
reset();
}
}

if(p2y+ph/2<by){
p2y+=ais;
} else {
p2y-=ais;
}

cc.fillStyle='black';
cc.fillRect(0,0,c.width,c.height);
cc.fillStyle='white';
cc.fillRect(0,p1y,pt,ph);
cc.fillRect(c.width-pt,p2y,pt,ph);
cc.fillRect(bx-bd/2,by-bd/2,bd,bd);
cc.fillText(score1,100,100);
cc.fillText(score2,c.width-100,100);

}
</script>


Command:

$ open html5game.html


Graphical result:

HTML5 & JavaScript Pong