I am coding virtual numerical keyboard. Can I please have an advice why my code doesn't work?

```html
<!DOCTYPE html>
<html>

<head>
  <style>
    @import url('https://fonts.googleapis.com/css2?family=Open+Sans:wght@300&display=swap');
    body {
      font-family: 'Open Sans', sans-serif;
    }
  </style>
</head>

<body>

  <input id="myInput" type="text" />
  <br /><br />
  <input type="button" value=1 onclick="input(1);" />
  <input type="button" value=2 onclick="input(2);" />
  <input type="button" value=3 onclick="input(3);" />
  <br />
  <input type="button" value=4 onclick="input(4);" />
  <input type="button" value=5 onclick="input(5);" />
  <input type="button" value=6 onclick="input(6);" />
  <br />
  <input type="button" value=7 onclick="input(7);" />
  <input type="button" value=8 onclick="input(8);" />
  <input type="button" value=9 onclick="input(9);" />
  <br /><br />
  <input type="button" value=backspace onclick="del();" />

  <script>
    function input(e) {
      var myInput = document.getElementById("myInput”);
        myInput.value = myInput.value + e.value;
      }

      function del() {
        var myInput = document.getElementById("myInput");
        myInput.value = myInput.value.substr(0, myInput.value.length - 1);
      }
  </script>

</body>

</html>
```

I am also thinking why do the buttons have different width, considering that Open Sans is a monospaced font...

Thank you.