Prism Diopter to Degree Converter

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  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Prism Diopter & Angle Converter</title>
  <style>
      body {
          font-family: Arial, sans-serif;
          margin: 20px;
          padding: 20px;
          max-width: 900px;
      }
      h2 {
          color: #333;
      }
      label {
          font-weight: bold;
      }
      input, button {
          margin-top: 5px;
          padding: 8px;
          font-size: 16px;
      }
      p {
          font-size: 18px;
          font-weight: bold;
          color: blue;
          margin-top: 10px;
      }
  </style>

</head> <body>

  <h2>Prism Diopter & Angle Converter</h2>

  <!-- Convert Angle to Prism Diopter -->
  <h3>Convert Degrees to Prism Diopters</h3>
  <label for="angleInput">Enter Angle (1-90 degrees): </label>
  <input type="number" id="angleInput" step="any" min="1" max="90">
  <button onclick="convertToDiopters()">Convert</button>
  <p id="resultDiopters"></p>
  <hr>
  <!-- Convert Prism Diopter to Angle -->
  <h3>Convert Prism Diopters to Degrees</h3>
  <label for="diopterInput">Enter Prism Diopters: </label>
  <input type="number" id="diopterInput" step="any">
  <button onclick="convertToAngle()">Convert</button>
  <p id="resultAngle"></p>

  <script>
      function convertToDiopters() {
          let angle = parseFloat(document.getElementById("angleInput").value);
          let resultElement = document.getElementById("resultDiopters");

          if (isNaN(angle) || angle < 1 || angle > 90) {
              resultElement.innerHTML = "Please enter an angle between 1 and 90 degrees.";
              return;
          }

          let prismDiopter = 100 * Math.tan(angle * (Math.PI / 180)); // Convert degrees to radians
          let roundedDiopter = Math.round(prismDiopter); // Round to whole number

          resultElement.innerHTML = `Prism Diopters: <b>${roundedDiopter}</b>`;
      }

      function convertToAngle() {
          let diopters = parseFloat(document.getElementById("diopterInput").value);
          let resultElement = document.getElementById("resultAngle");

          if (isNaN(diopters)) {
              resultElement.innerHTML = "Please enter a valid prism diopter value.";
              return;
          }

          let angle = Math.atan(diopters / 100) * (180 / Math.PI); // Convert radians to degrees
          let roundedAngle = Math.round(angle); // Round to whole number

          resultElement.innerHTML = `Angle: <b>${roundedAngle}°</b>`;
      }

      // Allow "Enter" key to trigger conversion
      document.getElementById("angleInput").addEventListener("keypress", function(event) {
          if (event.key === "Enter") {
              convertToDiopters();
          }
      });

      document.getElementById("diopterInput").addEventListener("keypress", function(event) {
          if (event.key === "Enter") {
              convertToAngle();
          }
      });
  </script>

</body> </html>

calculator

calculator prism