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I am using code from https://www.kirupa.com/html5/the_falling_snow_effect.htm and well as it turns out the snow is falling all over my page and not just the banner div...

// Array to store our Snowflake objects
var snowflakes = [];

// Global variables to store our browser's window size
var browserWidth;
var browserHeight;

// Specify the number of snowflakes you want visible
var numberOfSnowflakes = 50;

// Flag to reset the position of the snowflakes
var resetPosition = false;

// Handle accessibility
var enableAnimations = false;
var reduceMotionQuery = matchMedia("(prefers-reduced-motion)");

// Handle animation accessibility preferences 
function setAccessibilityState() {
  if (reduceMotionQuery.matches) {
    enableAnimations = false;
  } else {
    enableAnimations = true;
  }
}
setAccessibilityState();

reduceMotionQuery.addListener(setAccessibilityState);

//
// It all starts here...
//
function setup() {
  if (enableAnimations) {
    window.addEventListener("DOMContentLoaded", generateSnowflakes, false);
    window.addEventListener("resize", setResetFlag, false);
  }
}
setup();

//
// Constructor for our Snowflake object
//
function Snowflake(element, speed, xPos, yPos) {
  // set initial snowflake properties
  this.element = element;
  this.speed = speed;
  this.xPos = xPos;
  this.yPos = yPos;
  this.scale = 1;

  // declare variables used for snowflake's motion
  this.counter = 0;
  this.sign = Math.random() < 0.5 ? 1 : -1;

  // setting an initial opacity and size for our snowflake
  this.element.style.opacity = (.9 + Math.random()) / 3;
}

//
// The function responsible for actually moving our snowflake
//
Snowflake.prototype.update = function() {
  // using some trigonometry to determine our x and y position
  this.counter += this.speed / 5000;
  this.xPos += this.sign * this.speed * Math.cos(this.counter) / 40;
  this.yPos += Math.sin(this.counter) / 40 + this.speed / 30;
  this.scale = .5 + Math.abs(10 * Math.cos(this.counter) / 20);

  // setting our snowflake's position
  setTransform(Math.round(this.xPos), Math.round(this.yPos), this.scale, this.element);

  // if snowflake goes below the browser window, move it back to the top
  if (this.yPos > browserHeight) {
    this.yPos = -50;
  }
}

//
// A performant way to set your snowflake's position and size
//
function setTransform(xPos, yPos, scale, el) {
  el.style.transform = `translate3d(${xPos}px, ${yPos}px, 0) scale(${scale}, ${scale})`;
}

//
// The function responsible for creating the snowflake
//
function generateSnowflakes() {

  // get our snowflake element from the DOM and store it
  var originalSnowflake = document.querySelector(".snowflake");

  // access our snowflake element's parent container
  var snowflakeContainer = originalSnowflake.parentNode;
  snowflakeContainer.style.display = "block";

  // get our browser's size
  browserWidth = document.documentElement.clientWidth;
  browserHeight = document.documentElement.clientHeight;

  // create each individual snowflake
  for (var i = 0; i < numberOfSnowflakes; i++) {

    // clone our original snowflake and add it to snowflakeContainer
    var snowflakeClone = originalSnowflake.cloneNode(true);
    snowflakeContainer.appendChild(snowflakeClone);

    // set our snowflake's initial position and related properties
    var initialXPos = getPosition(50, browserWidth);
    var initialYPos = getPosition(50, browserHeight);
    var speed = 5 + Math.random() * 40;

    // create our Snowflake object
    var snowflakeObject = new Snowflake(snowflakeClone,
      speed,
      initialXPos,
      initialYPos);
    snowflakes.push(snowflakeObject);
  }

  // remove the original snowflake because we no longer need it visible
  snowflakeContainer.removeChild(originalSnowflake);

  moveSnowflakes();
}

//
// Responsible for moving each snowflake by calling its update function
//
function moveSnowflakes() {

  if (enableAnimations) {
    for (var i = 0; i < snowflakes.length; i++) {
      var snowflake = snowflakes[i];
      snowflake.update();
    }
  }

  // Reset the position of all the snowflakes to a new value
  if (resetPosition) {
    browserWidth = document.documentElement.clientWidth;
    browserHeight = document.documentElement.clientHeight;

    for (var i = 0; i < snowflakes.length; i++) {
      var snowflake = snowflakes[i];

      snowflake.xPos = getPosition(50, browserWidth);
      snowflake.yPos = getPosition(50, browserHeight);
    }

    resetPosition = false;
  }

  requestAnimationFrame(moveSnowflakes);
}

//
// This function returns a number between (maximum - offset) and (maximum + offset)
//
function getPosition(offset, size) {
  return Math.round(-1 * offset + Math.random() * (size + 2 * offset));
}

//
// Trigger a reset of all the snowflakes' positions
//
function setResetFlag(e) {
  resetPosition = true;
}
#snowflakeContainer {
  position: absolute;
  left: 0px;
  top: 0px;
  display: none;
}

.snowflake {
  position: fixed;
  background-color: #ffffff;
  user-select: none;
  z-index: 1000;
  pointer-events: none;
  border-radius: 50%;
  width: 10px;
  height: 10px;
}
<div class="mainbanner">
  <div id="snowflakeContainer">
    <span class="snowflake"></span>
  </div>
  <br>
  <center>
    <p class="topText" style="font-size:8vw;"> Welcome to the ultimate <br>sleepover experience</p><br><br><br>
    <p class="topText" style="font-size:4vw;"> By Ultimate Teepee Party</p>

    <br><br><br>
    <a class="btn_1" href="book.html">Book Your Party</a></center>


</div>

There has to be a way to make it show only inside that banner div and not the whole page?

markalex
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Aly G
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1 Answers1

3

if you take a look at snow demo page with inspect element, you will realise that the author embedded a whole html page into the page instead of using a div, the idea is that javascript browserHeight = document.documentElement.clientHeight refers to browser width, therefore unless modifying JS, the page only works in whole page, I could see no effect in your original code since the relative positioning is not handled well. refers to following working demo, which allows you to display the snow in whole page. if you only want the effect to apply to a certain element, try modifying the script calculation based on element position. or you can do what the author did, embed a doc into whole page

JsFiddle

<style>
  #snowflakeContainer {
    position: fixed;
    left: 0px;
    top: 0px;
    display: none;
    width: 100vw;
    height: 100vh;
  }

  .snowflake {
    position: fixed;
    background-color: #CCC;
    user-select: none;
    z-index: 1000;
    pointer-events: none;
    border-radius: 50%;
    width: 10px;
    height: 10px;
    background: red;
  }

  .banner {
    position: fixed;
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    flex-direction: column;
  }

  .title {
    font-size: 8vw;
  }

  .author {
    font-size: 4vw;
  }

</style>

<div id="snowflakeContainer">
  <span class="snowflake"></span>
  <div class="banner">
    <div class="title">
      Welcome to the ultimate
    </div>
    <div class="title">
      sleepover experience
    </div>

    <br />
    <br />
    <br />

    <div class="author">
      By Ultimate Teepee Party
    </div>

    <br />
    <br />
    <br />

    <a class="btn_1" href="book.html">Book Your Party</a>

  </div>
</div>

<script>
  // Array to store our Snowflake objects
  var snowflakes = [];

  // Global variables to store our browser's window size
  var browserWidth;
  var browserHeight;

  // Specify the number of snowflakes you want visible
  var numberOfSnowflakes = 50;

  // Flag to reset the position of the snowflakes
  var resetPosition = false;

  // Handle accessibility
  var enableAnimations = false;
  var reduceMotionQuery = matchMedia("(prefers-reduced-motion)");

  // Handle animation accessibility preferences 
  function setAccessibilityState() {
    if (reduceMotionQuery.matches) {
      enableAnimations = false;
    } else {
      enableAnimations = true;
    }
  }
  setAccessibilityState();

  reduceMotionQuery.addListener(setAccessibilityState);

  //
  // It all starts here...
  //
  function setup() {
    if (enableAnimations) {
      window.addEventListener("DOMContentLoaded", generateSnowflakes, false);
      window.addEventListener("resize", setResetFlag, false);
    }
  }
  setup();

  //
  // Constructor for our Snowflake object
  //
  function Snowflake(element, speed, xPos, yPos) {
    // set initial snowflake properties
    this.element = element;
    this.speed = speed;
    this.xPos = xPos;
    this.yPos = yPos;
    this.scale = 1;

    // declare variables used for snowflake's motion
    this.counter = 0;
    this.sign = Math.random() < 0.5 ? 1 : -1;

    // setting an initial opacity and size for our snowflake
    this.element.style.opacity = (.1 + Math.random()) / 3;
  }

  //
  // The function responsible for actually moving our snowflake
  //
  Snowflake.prototype.update = function() {
    // using some trigonometry to determine our x and y position
    this.counter += this.speed / 5000;
    this.xPos += this.sign * this.speed * Math.cos(this.counter) / 40;
    this.yPos += Math.sin(this.counter) / 40 + this.speed / 30;
    this.scale = .5 + Math.abs(10 * Math.cos(this.counter) / 20);

    // setting our snowflake's position
    setTransform(Math.round(this.xPos), Math.round(this.yPos), this.scale, this.element);

    // if snowflake goes below the browser window, move it back to the top
    if (this.yPos > browserHeight) {
      this.yPos = -50;
    }
  }

  //
  // A performant way to set your snowflake's position and size
  //
  function setTransform(xPos, yPos, scale, el) {
    el.style.transform = `translate3d(${xPos}px, ${yPos}px, 0) scale(${scale}, ${scale})`;
  }

  //
  // The function responsible for creating the snowflake
  //
  function generateSnowflakes() {

    // get our snowflake element from the DOM and store it
    var originalSnowflake = document.querySelector(".snowflake");

    // access our snowflake element's parent container
    var snowflakeContainer = originalSnowflake.parentNode;
    snowflakeContainer.style.display = "block";

    // get our browser's size
    browserWidth = document.documentElement.clientWidth;
    browserHeight = document.documentElement.clientHeight;

    // create each individual snowflake
    for (var i = 0; i < numberOfSnowflakes; i++) {

      // clone our original snowflake and add it to snowflakeContainer
      var snowflakeClone = originalSnowflake.cloneNode(true);
      snowflakeContainer.appendChild(snowflakeClone);

      // set our snowflake's initial position and related properties
      var initialXPos = getPosition(50, browserWidth);
      var initialYPos = getPosition(50, browserHeight);
      var speed = 5 + Math.random() * 40;

      // create our Snowflake object
      var snowflakeObject = new Snowflake(snowflakeClone,
        speed,
        initialXPos,
        initialYPos);
      snowflakes.push(snowflakeObject);
    }

    // remove the original snowflake because we no longer need it visible
    snowflakeContainer.removeChild(originalSnowflake);

    moveSnowflakes();
  }

  //
  // Responsible for moving each snowflake by calling its update function
  //
  function moveSnowflakes() {

    if (enableAnimations) {
      for (var i = 0; i < snowflakes.length; i++) {
        var snowflake = snowflakes[i];
        snowflake.update();
      }
    }

    // Reset the position of all the snowflakes to a new value
    if (resetPosition) {
      browserWidth = document.documentElement.clientWidth;
      browserHeight = document.documentElement.clientHeight;

      for (var i = 0; i < snowflakes.length; i++) {
        var snowflake = snowflakes[i];

        snowflake.xPos = getPosition(50, browserWidth);
        snowflake.yPos = getPosition(50, browserHeight);
      }

      resetPosition = false;
    }

    requestAnimationFrame(moveSnowflakes);
  }

  //
  // This function returns a number between (maximum - offset) and (maximum + offset)
  //
  function getPosition(offset, size) {
    return Math.round(-1 * offset + Math.random() * (size + 2 * offset));
  }

  //
  // Trigger a reset of all the snowflakes' positions
  //
  function setResetFlag(e) {
    resetPosition = true;
  }

</script>
Weilory
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