How to set and remove focus using jQuery

jQuery is a fast and concise JavaScript library. It encapsulates commonly used JavaScript tasks, making it easier for us to use JavaScript to complete a variety of operations. In web applications, focus is a very important concept, it represents which element on the page the user is interacting with. In this article, we will focus on how to set and remove focus using jQuery.

1. Set focus

In web applications, we usually need to set focus on an element in the page so that users can interact with the element. The most common use case is to set focus when the page loads. To set the focus, we can use jQuery’s .focus() method. This method has two uses:

1. Select an element and set focus

$('#element').focus();

In this example, we first use jQuery to select an element, and then on the element Call the .focus() method to set focus.

2. Chain call

$('#element').addClass('active').focus();

In this example, we first call the .addClass() method on the element to add a CSS class, and then Chain the .focus() method to set focus.

In addition to setting focus when the page loads, we can also set focus dynamically when the user interacts with the page. For example, we might want to set focus to an input box when the user clicks a button. To achieve this effect, we can use jQuery's event handling function:

$('#button').on('click', function() {
  $('#input').focus();
});

In this example, we use the .on() method to add a click event handler to the button. When the user clicks the button, the event handler will call the .focus() method on the input box to set the focus.

2. Remove focus

When we finish interacting with an element, we usually want to move the focus away from the element. To remove focus, we can use jQuery's .blur() method. This method has two uses:

1. Select an element and remove focus

$('#element').blur();

In this example, we first use jQuery to select an element, and then on the element Call the .blur() method to remove focus.

2. Chain call

$('#element').removeClass('active').blur();

In this example, we first call the .removeClass() method on the element to remove a CSS class. Then chain the .blur() method to remove focus.

In addition to removing focus when the user completes interaction with an element, we can also dynamically remove focus when the user performs other operations with the page. For example, we might want to move focus away from the current element when the user presses the Enter key. To achieve this effect, we can use jQuery's event handling function:

$(document).on('keydown', function(event) {
  if (event.keyCode === 13) {
    $(document.activeElement).blur();
  }
});

In this example, we use the .on() method to add a keyboard press event handler to the document. When the user presses the Enter key, the event handler will call the .blur() method on the currently focused element to remove focus.

Summary:

In this article, we introduced how to set and remove focus using jQuery. To set focus, we can use the .focus() method to select an element and set focus, or set focus dynamically in an event handler. To remove focus, we can use the .blur() method to select an element and remove focus, or dynamically remove focus in an event handler. These technologies can help us better manage focus in web applications and improve user interaction experience.

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