ADD file via upload

change——javascript.js

@@ -0,0 +1,28 @@
+document.getElementById('convert-btn').addEventListener('click', function() {
+    const number = document.getElementById('number-input').value;
+    const base = document.getElementById('base-select').value;
+
+    let result = '';
+
+    if (!isNaN(number) && number.trim() !== '') {
+        const decimalNumber = parseInt(number, 10);
+
+        switch (base) {
+            case '2':
+                result = decimalNumber.toString(2);
+                break;
+            case '8':
+                result = decimalNumber.toString(8);
+                break;
+            case '16':
+                result = decimalNumber.toString(16).toUpperCase();
+                break;
+            default:
+                result = '请选择一个有效的进制';
+        }
+    } else {
+        result = '请输入一个有效的数字';
+    }
+
+    document.getElementById('result').textContent = result;
+});