Now Bootstrap example works. Go to sleep.

index.html

@@ -23,7 +23,7 @@
                                 <div class="input-group-prepend">
                                     <span class="input-group-text" id="basic-addon1">Enter a positive integer</span>
                                 </div>
-                                <input type="text" class="form-control input-example" placeholder="1"
+                                <input type="text" class="form-control input-example" placeholder=""
                                     id="input-example-1" aria-label="positive-integer-1"
                                     aria-describedby="basic-addon1">
                             </div>
@@ -34,7 +34,7 @@
                                     <span class="input-group-text" id="basic-addon2">Enter another positive
                                         integer</span>
                                 </div>
-                                <input type="number" class="form-control input-example" placeholder="2"
+                                <input type="text" class="form-control input-example" placeholder=""
                                     id="input-example-2" aria-label="positive-integer-2"
                                     aria-describedby="basic-addon2">
                             </div>
@@ -44,14 +44,7 @@
                     </tr>
                 </tbody>
             </table>
-            <div>
-                <button type="button" class="btn btn-primary btn-example" id="btn-example">Calculate</button>
-            </div>
-            <hr>
-                <p id="card-example-result">
-                  This is some text within a card body.
-                </p>
-              </div>
+            <p id="card-example-result"></p>
         </div>
     </div>
 

new_example.js

 $("#card-example-result").text("");
-$('.input-example').val("1");
+$('.input-example').val("0");
 $(".input-example").keyup(function () {
     let s = $(this).val();
     s = s.replace(/\D/g, '');
-    $(this).val(s);
-});
-$("#btn-example").click(function () {
-    let a = $("#input-example-1").val();
-    let b = $("#input-example-2").val();
+    $(this).val(+s);                         
+// });
+// $("#btn-example").click(function () {
+    let a = +$("#input-example-1").val();
+    let b = +$("#input-example-2").val();      
     let gcd = getGreatestCommonDivisor(a, b);
     $("#card-example-result").text(`Greatest common divisor = ${gcd}`);
 });
+
 function getGreatestCommonDivisor(a, b) {
     // See https://www.geeksforgeeks.org/c-program-find-gcd-hcf-two-numbers/
     if (b == 0) return a;