elemnet onchange do something in javascript

In order to trigger a function when an element's value changes, we can use an onchange event listener. Here's an example of how to implement it:

index.tsx
const inputElement = document.getElementById('my-input');

inputElement.addEventListener('change', function(event) {
  // Do something when the input value changes, for example:
  const newValue = event.target.value;
  console.log(newValue);
});
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In the example, we first get the input element by its ID using document.getElementById. Then we attach an event listener to it using addEventListener. The first argument is the event we listen to, which in this case is 'change'. The second argument is the callback function that will be executed when the event occurs.

Inside the callback function, we can access the new value of the input element using event.target.value. We can then do whatever we want with that value, for example logging it to the console.

Note that the onchange event only fires when the input element loses focus and its value has changed. If you want to react to every keystroke, you can use the oninput event instead.