OnBlur vs OnChange in React: Event Handling in Modern Web Apps

Building forms in React applications may help users interact and enable them to provide feedback, share information, etc. But to make these forms more user-friendly, what can you do? What features can you add to impress the users and excite them? Well, the answer is- OnBlur and OnChange in React.

Onblur event in React is triggered when a user moves the focus away from an input field. It is helpful to detect when a user has finished editing an input field, even if they didn’t change the value. On the other hand, an Onchange event triggers when there is a change in the value of an input field. 

Onblur and Onchange events have different use cases and behaviors. Hence, knowing when to use each can help you build a more efficient and accessible application. So, first, let’s learn about the onBlur event in React.

Onblur In React

The Onblur event is triggered when a user moves the focus away from an input field. This event is worthwhile when you want to detect when a user has finished editing a lot, even if they didn’t change the value. For example, you might use onblur to validate an input field, save the input data to the server, or update the user interface based on the input.

Here is an example of using Onblur in React:

function MyInput() {
const [value, set Value] = useState('');
const handleBlur = () => {
console.log ('Input blurred'); 
};
const handleChange = (event) => { 
setValue(event.target.value);
};
return (
<input 
type= "text" 
value={value}
onBlur={handleBlur}
onChange={handleChange}
/>
); 
}

In this example, we have an input field that uses onblur and onchange. When the user moves the focus away from the input field, the “handleBlur function” is called, which logs a message to the console. The “handleChange function” pops when the user types in the input field and updates the value state with the new one.

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Onchange In React

If there is a change in the value of an input field, then it will trigger the Onchange event. This event is valuable when you want to detect when a user has modified the value of an input field. For example, you might use onchange to update the value of a dependent lot, enable or disable a button based on the input, or validate the input as the user types.

Here is an example of using onchange in React:

function MyInput() { 
const [value, setValue] = useState('');
const handleChange = (event) => {
setValue(event.target.value);
};
return (
<input
type= "text"
value={value}
onChange={handleChange}
/>
);
}

In this example, we have an input field that uses onchange to update the value state whenever the user types into the input field. The “handleChange function” pops when the user types in the input field and updates the value state with the new one.

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Onblur Vs Onchange In React

Now that we have seen how Onblur and Onchange work in React, let’s compare them based on their use cases and behavior.

Use cases

• Use onblur to detect when a user has finished editing an input field, even if they didn’t change the value.
• Use onchange when you want to see when a user has modified the value of an input field.

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Behavior

• Whenever a user moves away the focus from the input field, Onblur triggers.
• If the user changes the input field’s value, then Onchange triggers.
• Onblur is not triggered when the user types into an input field but does not move the focus away from it.
• Onchange is triggered every time the user types into an input field, even if they still need to finish editing it.

Performance

When it comes to performance, Onblur is generally less resource-intensive than Onchange. This is because onblur is triggered only once when the user finishes editing the field, while onchange is triggered multiple times as the user types into the field. Therefore, if you are dealing with a large number of input fields, using onblur can help reduce the number of unnecessary updates to the state and improve the overall performance of your application.

Accessibility

Another important consideration when working with form inputs is accessibility. Both onblur and onchange can be used to improve the accessibility of your application. But they are suited for different scenarios.

For example, if you have a form with many input fields, it may be helpful to use onblur to detect when a user has finished editing a field. Then provide feedback or validation messages to the user. On the other hand, if you have a form with dependent fields or conditional logic, using onchange can help ensure that the form behaves predictably. It is easy to navigate for users with assistive technologies.

FAQs

Conclusion

In summary, both onblur and onchange are important events in React that are used to handle user input. One can often need clarification about how similar they are. However, they are different in usage and behaviors.

Use onblur when you want to detect when a user has finished editing an input field. Use onchange when you want to detect when a user has modified the value of an input field. Consider performance and accessibility when choosing between these events. Use them appropriately to build robust and user-friendly forms in your React applications.

Louis Bouchard

I am focusing on making AI accessible. I try to share and explain artificial intelligence terms and news the best way I can for everyone.