JavaScript30/03-CSSVariables/index.html at master · komecodes/JavaScript30 · GitHub

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <title>Scoped CSS Variables and JS</title>
    <link rel="stylesheet" href="style.css">
  </head>
  <body>
    <div class="container">
      <h2>Update CSS Variables with <span class="highlight">JS</span></h2>

      <div class="controls">
        <div>
          <label for="spacing">Spacing: </label>
          <div class="input-container">
            <input
              id="spacing"
              type="range"
              name="spacing"
              min="10"
              max="200"
              value="10"
              data-sizing="px"
            />
          </div>
        </div>

        <div>
          <label for="blur">Blur: </label>
          <div class="input-container">
            <input
              id="blur"
              type="range"
              name="blur"
              min="0"
              max="25"
              value="10"
              data-sizing="px"
            />
          </div>
        </div>
        <div>
          <label for="base">Base Color: </label>
          <div class="input-container">
            <input id="base" type="color" name="base" value="#f33f3f" />
          </div>
        </div>
      </div>

      <div class="image-block">
        <img src="https://source.unsplash.com/7bwQXzbF6KE/800x500" />
      </div>
    </div>

    <script>
      const inputs = document.querySelectorAll(".controls input");
      inputs.forEach((input) => input.addEventListener("change", handleUpdate));
      inputs.forEach((input) =>
        input.addEventListener("mousemove", handleUpdate)
      );

      // This function checks the root element and updates the css variables created on it with the value of the input element, when there's a change or mouve move event. Note that we gave names to the input elements that corresponds with the variable names we set on the root element, hence this.name.

      function handleUpdate() {
        // To get the "px', assign the data attribute created in the HTML to a variable, then concatenate the string to the input value. This is because the inputs spacing and blur will always be a number but to make it a valid css value, we need to add the unit (px).

        // Base Color is already a valid css string value and we'll not need to attach px, hence, the; or empty string (|| " ").

        const valueSuffix = this.dataset.sizing || "";
        document.documentElement.style.setProperty(
          `--${this.name}`,
          this.value + `${valueSuffix}`
        );
      }
    </script>
  </body>
</html>