Effect with js and svg only works in the first class in the second effect does not apply

I have a problem with my effect on svg I added a triangles effect with svg and js on one of my sessions site as you can see works normally but I needed to put this effect again in another session I'm calling the effect via class and not id but it does not work it only works in the first session follow the photos First session working:

Secondsessiondoesnotwork:

Noticethateventrianglesdonotappearbecause?soIunderstandthejavascriptisonlycatchingthefirstclassandtheseconditdoesnotfindsoitdoesnotactivatetheeffectitfollowsmycodes:

HTML:

JS:

/*SVGBackground*/varrefreshDuration=6000;varrefreshTimeout;varnumPointsX;varnumPointsY;varunitWidth;varunitHeight;varpoints;functiononLoad(){varsvg=document.createElementNS('http://www.w3.org/2000/svg','svg');svg.setAttribute('width',window.innerWidth);svg.setAttribute('height',window.innerHeight);document.querySelector(".bg").appendChild(svg);

            var unitSize = (window.innerWidth+window.innerHeight)/20;
            numPointsX = Math.ceil(window.innerWidth/unitSize)+1;
            numPointsY = Math.ceil(window.innerHeight/unitSize)+1;
            unitWidth = Math.ceil(window.innerWidth/(numPointsX-1));
            unitHeight = Math.ceil(window.innerHeight/(numPointsY-1));

            points = [];

            for(var y = 0; y < numPointsY; y++) {
                for(var x = 0; x < numPointsX; x++) {
                    points.push({x:unitWidth*x, y:unitHeight*y, originX:unitWidth*x, originY:unitHeight*y});
                }
            }

            randomize();

            for(var i = 0; i < points.length; i++) {
                if(points[i].originX != unitWidth*(numPointsX-1) && points[i].originY != unitHeight*(numPointsY-1)) {
                    var topLeftX = points[i].x;
                    var topLeftY = points[i].y;
                    var topRightX = points[i+1].x;
                    var topRightY = points[i+1].y;
                    var bottomLeftX = points[i+numPointsX].x;
                    var bottomLeftY = points[i+numPointsX].y;
                    var bottomRightX = points[i+numPointsX+1].x;
                    var bottomRightY = points[i+numPointsX+1].y;

                    var rando = Math.floor(Math.random()*2);

                    for(var n = 0; n < 2; n++) {
                        var polygon = document.createElementNS(svg.namespaceURI, 'polygon');

                        if(rando==0) {
                            if(n==0) {
                                polygon.point1 = i;
                                polygon.point2 = i+numPointsX;
                                polygon.point3 = i+numPointsX+1;
                                polygon.setAttribute('points',topLeftX+','+topLeftY+' '+bottomLeftX+','+bottomLeftY+' '+bottomRightX+','+bottomRightY);
                            } else if(n==1) {
                                polygon.point1 = i;
                                polygon.point2 = i+1;
                                polygon.point3 = i+numPointsX+1;
                                polygon.setAttribute('points',topLeftX+','+topLeftY+' '+topRightX+','+topRightY+' '+bottomRightX+','+bottomRightY);
                            }
                        } else if(rando==1) {
                            if(n==0) {
                                polygon.point1 = i;
                                polygon.point2 = i+numPointsX;
                                polygon.point3 = i+1;
                                polygon.setAttribute('points',topLeftX+','+topLeftY+' '+bottomLeftX+','+bottomLeftY+' '+topRightX+','+topRightY);
                            } else if(n==1) {
                                polygon.point1 = i+numPointsX;
                                polygon.point2 = i+1;
                                polygon.point3 = i+numPointsX+1;
                                polygon.setAttribute('points',bottomLeftX+','+bottomLeftY+' '+topRightX+','+topRightY+' '+bottomRightX+','+bottomRightY);
                            }
                        }
                        polygon.setAttribute('fill','rgba(0,0,0,'+(Math.random()/3)+')');
                        var animate = document.createElementNS('http://www.w3.org/2000/svg','animate');
                        animate.setAttribute('fill','freeze');
                        animate.setAttribute('attributeName','points');
                        animate.setAttribute('dur',refreshDuration+'ms');
                        animate.setAttribute('calcMode','linear');
                        polygon.appendChild(animate);
                        svg.appendChild(polygon);
                    }
                }
            }

            refresh();

        }

        function randomize() {
            for(var i = 0; i < points.length; i++) {
                if(points[i].originX != 0 && points[i].originX != unitWidth*(numPointsX-1)) {
                    points[i].x = points[i].originX + Math.random()*unitWidth-unitWidth/2;
                }
                if(points[i].originY != 0 && points[i].originY != unitHeight*(numPointsY-1)) {
                    points[i].y = points[i].originY + Math.random()*unitHeight-unitHeight/2;
                }
            }
        }

        function refresh() {
            randomize();
            for(var i = 0; i < document.querySelector(".bg svg").childNodes.length; i++) {
                var polygon = document.querySelector(".bg svg").childNodes[i];
                var animate = polygon.childNodes[0];
                if(animate.getAttribute('to')) {
                    animate.setAttribute('from',animate.getAttribute('to'));
                }
                animate.setAttribute('to',points[polygon.point1].x+','+points[polygon.point1].y+' '+points[polygon.point2].x+','+points[polygon.point2].y+' '+points[polygon.point3].x+','+points[polygon.point3].y);
                animate.beginElement();
            }
            refreshTimeout = setTimeout(function() {refresh();}, refreshDuration);
        }

        function onResize() {
            document.querySelector(".bg svg").remove();
            clearTimeout(refreshTimeout);
            onLoad();
        }

        window.onload = onLoad;
        window.onresize = onResize;

NOTE: Code from this site here