<!DOCTYPE html>
<html>
<head>
  <title>Wheel Offset Calculator</title>
</head>
<body>
  <h1>Wheel Offset Calculator</h1>
  <form>
    <label for="diameter">Wheel Diameter (inches):</label>
    <input type="number" id="diameter" name="diameter">
    <br>
    <label for="tire_width">Tire Width (inches):</label>
    <input type="number" id="tire_width" name="tire_width">
    <br>
    <label for="rim_width">Rim Width (inches):</label>
    <input type="number" id="rim_width" name="rim_width">
    <br>
    <button type="button" onclick="calculate()">Calculate</button>
  </form>
  <p id="result"></p>
  
  <script>
    function calculate() {
      // Get the input values
      var diameter = document.getElementById("diameter").value;
      var tire_width = document.getElementById("tire_width").value;
      var rim_width = document.getElementById("rim_width").value;
      
      // Half of the Tire Width
      var half_tire = tire_width/2;
      
      // Half of the Rim Width
      var half_rim = rim_width/2;
      
      // Wheel Offset Calculation
      var offset = (diameter/2) - (half_tire + half_rim);
      
      // Display the Result
      document.getElementById("result").innerHTML = "Wheel Offset: " + offset + " inches";
    }
  </script>
</body>
</html>