List-Virtualization-Discussion/square.html at main · JuneLin2001/List-Virtualization-Discussion · GitHub

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<!DOCTYPE html>
<html lang="zh-TW">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>正方形生成器</title>
    <style>
      #square {
        background-color: lightblue;
        display: none;
      }
    </style>
  </head>
  <body>
    <h2>
      這是一個簡單的繪製正方形功能，透過輸入一個超大的值（如100000000px），看實際大小會是幾px。
    </h2>
    <h3>輸入正方形的邊長</h3>
    <input type="number" id="sizeInput" placeholder="輸入數字" />
    <button onclick="generateSquare()">確定</button>
    <div>目前正方形的寬度是：<span id="squareWidth"></span></div>

    <div id="square"></div>

    <script>
      function generateSquare() {
        const size = document.getElementById("sizeInput").value;
        const square = document.getElementById("square");
        const squareWidthDisplay = document.getElementById("squareWidth");

        if (size > 0) {
          square.style.width = size + "px";
          square.style.height = size + "px";
          square.style.display = "block";

          setTimeout(() => {
            const actualWidth = square.offsetWidth;
            squareWidthDisplay.textContent = `${actualWidth}px`;
          }, 0);
        } else {
          alert("請輸入有效的數字");
          square.style.display = "none";
          squareWidthDisplay.textContent = "";
        }
      }
    </script>
  </body>
</html>