Which event listener in the DOM API should I use to trigger an action when a form field is focused, whether through a mouse click or by tabbing?

Question

Which event listener in the DOM API should I use to trigger an action when a form field is focused, whether through a mouse click or by tabbing?

My aim is to increase the size of form fields when the cursor focuses on them, either through a mouse click or by tabbing using the keyboard.

By utilizing document.activeElement focus, I can identify when the user clicks inside a text input or selects an element.

The issue arises when users navigate to the select list using the tab key only. In this scenario, if a user presses tab and reaches the select list element without using the mouse, the focus event will not trigger, causing the select list not to be resized.

Which event would indicate if the cursor is currently positioned on a select element while pressing the tab key alone?

javascript html jquery css

Answer 1

Answer №1

By using pure vanilla JavaScript, you have the ability to easily target and manipulate a specific input field within your document. Utilizing the querySelector function provided by the document object allows you to select the desired input field. You can then add an eventListener to this reference, specifically listening for 'focus' events. These events will trigger regardless of how the user interacts with the component - whether it be via Tab key or mouse click.

For reference, here is a concise example sourced from the MDN documentation.

   //HTML
    
    <form id="form">
      <input type="text" placeholder="text input">
    </form>
    
    //JavaScript
    
    const textInstance = document.querySelector('input[type="text"]');
  
    textInstance .addEventListener('focus', (event) => {
// Here, you have the flexibility to apply CSS styling changes, such as enlarging the field. In the provided example, it adjusts the background color to pink.
      event.target.style.background = 'pink';    
    });

Answer 2

By using pure vanilla JavaScript, you have the ability to easily target and manipulate a specific input field within your document. Utilizing the querySelector function provided by the document object allows you to select the desired input field. You can then add an eventListener to this reference, specifically listening for 'focus' events. These events will trigger regardless of how the user interacts with the component - whether it be via Tab key or mouse click.

For reference, here is a concise example sourced from the MDN documentation.

   //HTML
    
    <form id="form">
      <input type="text" placeholder="text input">
    </form>
    
    //JavaScript
    
    const textInstance = document.querySelector('input[type="text"]');
  
    textInstance .addEventListener('focus', (event) => {
// Here, you have the flexibility to apply CSS styling changes, such as enlarging the field. In the provided example, it adjusts the background color to pink.
      event.target.style.background = 'pink';    
    });

Which event listener in the DOM API should I use to trigger an action when a form field is focused, whether through a mouse click or by tabbing?

Answer №1

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