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optional "snow falling" theme

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  • Hi @phenomlab , around Christmas time, we use this “custom header” which basically creates a snow effect on the screen.

    <script src=""></script>

    However, last year some users who were on desktops using Windows and Google chrome were complaining that this custom header increased CPU usage a lot.

    I wonder if it is possible to create a button switch on the navigation bar which will be on as default, and if users want, they can turn it off, and snow falling can stop.

    Of course, this will be a temporary button. I am not looking for a permanent change since we will remove the snow-falling effect right after the new year.

  • I’m doing this last year but for another JS script.

    I leave the code. Maybe you can take inspiration from it (or not)

    You can add button with HTML widget like this (adapt the code for your JS script) :

    HTML :

    <!-- Start/Stop button  -->
    <button id='fall'>Start/Stop Animation</button>
    <!--Add DIV for CSS Snow -->
    <div class='snowc'></div>


    /* ---- Snow fall animation -*/
    /*Snow fall animation */
    .snowc {
        position: fixed;
        overflow: hidden;
        z-index: 0;
        height: 100%;
        width: 100%;
        pointer-events: none;
    .snowc.paused .snow {
        -webkit-animation-play-state: paused;
        animation-play-state: paused;
    .snow {
        position: absolute;
        top: -3%;
    .snow-div {
        border-radius: 50%;
        height: 5px;
        width: 5px;
    .snow svg {
        fill: #fff;
        height: 15px;
        width: 15px;
    /*Start/Stop button */
    #fall {
        position: absolute;
        border: 1px solid lightgrey;
        border-radius: 5px;
        Background: #F5F5F5;
        top: 64px;
        left: 15px;
        z-index: 1;
        /*cursor: pointer;*/
        /*cursor: url( , pointer;*/
        cursor: url( , pointer;
        font-weight: normal;
        /*background: #FF9700;*/
         opacity: 1;
    .fall {border-radius: 15px;}
    /* Rotation */
    @keyframes snow-rotate{
            transform: rotate(0deg);
            transform: rotate(360deg);

    JS :

    /* ---- Snow fall animation -*/
    var snow = {
        animate: true,
        containerSelector: '.snowc',
        particleCount: 0,
        particles: [300, 300],
        sizes: [25, 40],
        svgHeights: [15, 30], // Tailles pour les SVG
        svgWidths: [15, 30], // Tailles pour les SVG
        heights: [4, 6],
        widths: [4, 6],
        speeds: [12, 15],
        delay: [0, 11],
        rotate: true, // Rotation à la tombée
        useWind: true,
        windBlowingEast: true,
        windLinear: true, // Le vent dérive en tombant ou file tout droit jusqu'au point final
        windStrength: 1,
        useSvg: false, // Utilise SVG au lieu de div stylisée
        SVG: '<svg version="1.1" id="Capa_1" xmlns="" xmlns:xlink="" x="0px" y="0px" width="36.073px" height="36.073px" viewBox="0 0 36.073 36.073" style="enable-background:new 0 0 36.073 36.073;" xml:space="preserve"><g><path d="M33.526,19.58l-8.045,2.153l-6.404-3.697l6.404-3.698l8.045,2.155c0.045,0.013,0.091,0.018,0.136,0.018 c0.23,0,0.44-0.153,0.501-0.387c0.074-0.278-0.09-0.563-0.368-0.638l-7.038-1.885l6.708-3.874c0.248-0.144,0.333-0.462,0.19-0.711 c-0.146-0.25-0.464-0.334-0.712-0.19l-6.705,3.873l1.886-7.037c0.073-0.278-0.091-0.563-0.368-0.638 c-0.277-0.073-0.562,0.09-0.638,0.369l-2.155,8.042l-6.404,3.698V9.739l5.887-5.889c0.204-0.203,0.204-0.533,0-0.737 c-0.202-0.203-0.533-0.203-0.736,0l-5.151,5.153V0.521C18.558,0.234,18.324,0,18.037,0c-0.287,0-0.521,0.234-0.521,0.521v7.745 l-5.151-5.153c-0.204-0.203-0.534-0.203-0.737,0c-0.203,0.204-0.203,0.534,0,0.737l5.888,5.889v7.396l-6.405-3.698L8.956,5.394 C8.88,5.116,8.596,4.952,8.318,5.025C8.04,5.099,7.875,5.385,7.949,5.663l1.885,7.037L3.128,8.826 C2.88,8.683,2.561,8.767,2.417,9.017c-0.144,0.249-0.058,0.568,0.19,0.711l6.708,3.874l-7.039,1.885 C2,15.561,1.834,15.847,1.909,16.124c0.062,0.233,0.272,0.387,0.502,0.387c0.045,0,0.09-0.005,0.135-0.018l8.045-2.155l6.404,3.698 l-6.403,3.697l-8.045-2.154c-0.275-0.071-0.563,0.091-0.637,0.368C1.835,20.225,2,20.51,2.278,20.585l7.039,1.884l-6.708,3.874 c-0.249,0.145-0.334,0.462-0.19,0.712c0.097,0.167,0.272,0.261,0.452,0.261c0.088,0,0.178-0.021,0.26-0.069l6.708-3.874 L7.952,30.41c-0.074,0.278,0.091,0.563,0.369,0.637c0.045,0.013,0.091,0.019,0.136,0.019c0.229,0,0.439-0.153,0.502-0.387 l2.155-8.042l6.404-3.699v7.396l-5.887,5.89c-0.204,0.202-0.204,0.533,0,0.737c0.203,0.201,0.533,0.201,0.736,0l5.151-5.153v7.746 c0,0.286,0.233,0.521,0.521,0.521c0.287,0,0.521-0.234,0.521-0.521v-7.746l5.15,5.153c0.103,0.102,0.236,0.151,0.369,0.151 c0.135,0,0.268-0.052,0.368-0.151c0.204-0.204,0.204-0.535,0-0.737l-5.89-5.89v-7.394l6.403,3.697l2.155,8.044 c0.062,0.232,0.273,0.385,0.502,0.385c0.045,0,0.09-0.004,0.136-0.017c0.278-0.075,0.442-0.36,0.368-0.639l-1.888-7.035 l6.708,3.872c0.083,0.049,0.172,0.071,0.261,0.071c0.18,0,0.354-0.095,0.452-0.261c0.144-0.25,0.059-0.567-0.19-0.713l-6.708-3.873 l7.038-1.886c0.279-0.073,0.443-0.36,0.368-0.637C34.09,19.668,33.806,19.505,33.526,19.58z"/></g></svg>',
        init: function(){
        generateParticleCount: function(){
            this.particleCount = this.particles[0] + (Math.round(Math.random() * (snow.particles[1] - snow.particles[0])));
        appendHTML: function(jqselector){
            var html = this.generateHTML();
        generateHTML: function(){
            var html = '';
            for(var i=0; i<this.particleCount;i++)
                    html += '<div class="snow snow-particle-'+i+'">';
                    html += this.SVG;
                    html += '</div>';
                    html += '<div class="snow snow-div snow-particle-'+i+'"></div>';
            return html;
        appendCSS: function(){
            var css = this.generateCSS();
            css = '<style>' + css + '</style>';
        generateCSS: function(){
            var css = '';
            for(var i=0;i<this.particleCount;i++)
                width  = this.widths[0]  + Math.round(Math.random()  * (this.widths[1] - this.widths[0]));
                height = this.heights[0] + Math.round(Math.random() * (this.heights[1] - this.heights[0]));
                time = this.speeds[0] + Math.random() * (this.speeds[1] - this.speeds[0]);
                delay = this.delay[0] + Math.random() * (this.delay[1] - this.delay[0]);
                rotateTime = Math.random() + 1;
                    startingLeft = Math.round(Math.random() * 100);
                        startingLeft = Math.round(Math.random() * 200) - 100;
                        endLeftPos = startingLeft + (Math.round(Math.random() * (this.windStrength * 50)));
                        startingLeft = Math.round(Math.random() * 200) + 100;
                        endLeftPos = startingLeft - (Math.round(Math.random() * (this.windStrength * 50)));
                css += '.snow-particle-' + i + '{';
                css += 'left:' + startingLeft + '%;';
                    css += 'width: ' + width  + 'px;';
                    css += 'height: '+ height + 'px;';
                  css += 'animation: '+time+'s infinite ease-in anim-snow-particle-' + i + ', snow-rotate infinite '+rotateTime+'s linear;';
                  css += 'animation-delay: ' + delay + 's;';
                  css += 'top:'  + endLeft + 'vh;';
                css += '}';
                    svgWidth  = this.svgWidths[0]  + Math.round(Math.random()  * (this.svgWidths[1] - this.svgWidths[0]));
                    svgHeight = this.svgHeights[0] + Math.round(Math.random() * (this.svgHeights[1] - this.svgHeights[0]));
                    css += '.snow-particle-' + i + ' svg{';
                    css + 'height: ' + svgHeight;
                    css + 'width: ' + svgWidth;
                    css += '}';
                  css += '@keyframes anim-snow-particle-'+i+'{';
                  css += '100%{';
                  css += 'top: 101%;';
                      css += 'left: '+endLeftPos+'%';
                  css += '}';
                  css += '}';
            return css;


  • @crazycells the problem with JS scripts that execute animations is that they are being run in continuous loop. This presents the unwanted artifact of increasing the CPU cycles required to run it. In addition, with increasing CPU cycles will also come with increasing RAM which is being used to buffer in order to not overwhelm the CPU completely.

    There are two mechanisms you can use to prevent this. The “cheap” way is to include a pause function in the loop, or another statement that forces the current loop to close and be replaced with another (but with a very low time threshold to make it look like it’s not there at all).

    The other way is to “convince” the browser that it is supposed to be rendering 3D animation, which in turn, will then use hardware acceleration (unless the user disabled this) and offload the processing to the GPU instead. Traditionally, you’d use this css element to perform that

    transform: translateZ(0);

    There’s a more in depth explanation here

    In general, animations using JS can be quite unforgiving when it comes to performance. Executing onFocus is perfectly feasible as the process is killed onLeave or onMouseOut.

    Having an “on/off” button on the header or footer should ideally have a way of killing the loop - otherwise, it’ll continue to run without the animation giving you the false sense that everything is fine whilst it merrily chews CPU cycles in the background.

    Having completed the scripts that @DownPW and yourself have provided, my preference would be to use @DownPW version as it contains better coding methodology and gives you direct control over the CSS.

  • @DownPW thanks for the codes. 👍

  • If it were me, I would have created snowflake.min.js file and add this code

     License: Apache License 2.0
    (function(h,l){function p(){this.x=e(f);this.y=e(-1*g);this.r=.5+e(3);this.a=.3+e(.7);this.c=1+e(3);this.b=.5-e()}function q(){h.requestAnimationFrame(q);c.clearRect(0,0,f,g);for(var b=0;b<m;b++)a=n[b],a.y+=a.c,a.x+=a.b,a.y>g||a.x>f||0>a.x?n[b]=new p:0<a.y&&(c.globalAlpha=a.a,c.beginPath(),c.arc(a.x,a.y,a.r,0,2*Math.PI,!1),c.closePath(),c.fill())}function r(){var b=l.documentElement,a=l.body;f=h.innerWidth||b.clientWidth||a.clientWidth;g=h.innerHeight||b.clientHeight||a.clientHeight;m=f*g/7500>>0;k.width=f;k.height=g;c.fillStyle="#FFF";n=Array(m);for(b=0;b<m;b++)n[b]=new p}function e(a){return Math.random()*(a||1)}function t(a,c,d){a.addEventListener?a.addEventListener(c,d,!1):a.attachEvent("on"+c,d)}var k=l.createElement("canvas"),c=k.getContext("2d"),,f,g,m,n,a;d.position="fixed";"0";d.left="0";d.width="100%";d.height="100%";d.zIndex="999999";d.pointerEvents="none";t(h,"load",function(){r();q();l.body.appendChild(k)});t(h,"resize",r)})(window,document);

    Then change my html code to point to the Js file I hosted, just to reduce the amount of lookups

  • @Sala ok, but that’s still the same loop which is going to have an impact on the CPU.

  • phenomlabundefined phenomlab has marked this topic as solved on

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