javascript press enter not submit

In Web development, JavaScript is an indispensable programming language. In many cases, we need to capture some user operations, such as the Enter key, to achieve specific interactive effects. However, sometimes we don’t want the default form submission behavior of the Enter key to occur. What should we do in this case? This article will introduce how to prevent the default submit event of the Enter key through JavaScript.

Default behavior of the Enter key

In most web forms, when the user presses the Enter key in a single-line text box, the form is automatically submitted. This is the default behavior that comes with the browser, and may not be suitable for some interactive effects, such as a simple search box. When a user enters a keyword in the search box and presses the Enter key, if the default submission behavior is not prevented, the browser will automatically refresh the page and the keywords entered by the user will be lost.

Prevent the default submission event of the Enter key

To prevent the default submission event of the Enter key, you can use the event.preventDefault() method in JavaScript. This method can prevent the element's default behavior, such as preventing the form's default submit event.

Suppose we have the following HTML code:

<form>
  <input type="text" id="search-input">
</form>

We can prevent the default form submission event of the Enter key through the following JavaScript code:

const searchInput = document.querySelector('#search-input');
searchInput.addEventListener('keydown', (event) => {
  if (event.keyCode === 13) {
    event.preventDefault();
    console.log('阻止回车键默认提交事件');
  }
});

In the above code, We added a keydown event listener to the input box, which will be triggered when the user presses the keyboard. In the event handler, we determine whether the user pressed the Enter key, and if so, call event.preventDefault() to prevent the form's default submission event. At the same time, we output a message to the console so that we can verify whether the code is effective.

In addition to preventing the default submission event of the form, we can also execute our own JavaScript code after the event.preventDefault() method to achieve specific interactive effects.

Other Notes

When implementing preventing the Enter key from submitting events, you need to pay attention to the following points:

1. The event.preventDefault() method only handles events The default behavior inside the program is in effect, if the method is called outside the event handler, it will have no effect.
2. In the keydown event, we can obtain the key code pressed by the user through event.keyCode. The key code of the Enter key is 13.
3. In some cases, such as when the logic of the enter key needs to be processed in the search box while allowing the form to be submitted normally, we can solve this problem through event bubbling. In the keydown event handler of the search box, if we do not prevent the default behavior, the event will bubble up to the form element, thereby triggering the form's default submission event. Therefore, we can add a submit event listener on the form element and execute our own code when the form is submitted.

const form = document.querySelector('form');
form.addEventListener('submit', (event) => {
  event.preventDefault();
  console.log('表单被提交！');
})

Conclusion

JavaScript can easily prevent the Enter key from submitting events by default, thereby achieving a more free interaction effect. We can prevent the default behavior of the form through the event.preventDefault() method to achieve the interactive effect we need. At the same time, we also need to be careful about when and how to prevent default behavior in event handlers to avoid unexpected errors.

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