Check if an Element is Read-Only using JavaScript

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Borislav Hadzhiev

Tue Jan 11 20222 min read

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Check if an Element is Read-Only using JavaScript #

Use the readOnly property to check if an element is read-only, e.g. if (element.readOnly) {}. The readOnly property returns true when the element is read-only, otherwise false is returned.

Here is the HTML for the examples in this article.

index.html
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8" /> </head> <body> <input readonly type="text" id="first_name" name="first_name" value="James" /> <script src="index.js"></script> </body> </html>

And here is the related JavaScript code.

index.js
const element = document.getElementById('first_name'); console.log(element.readOnly); // 👉️ true if (element.readOnly) { console.log('✅ element is read-only'); } else { console.log('⛔️ element is not read-only'); } // ✅ Set attribute readonly // element.setAttribute('readonly', '') // ✅ Remove attribute readonly // element.removeAttribute('readonly');

The readOnly property on an element returns true if the element is read-only and false otherwise.

When the readonly attribute is set on the element, the element is not mutable and cannot be edited by the user.

You should always use the readOnly property to check if an element is read-only.

Some examples online use the getAttribute() method on the element, however boolean attributes like readonly might not have a value.

index.js
const element = document.getElementById('first_name'); // 👇️ returns empty string console.log(element.getAttribute('readonly')); // ❌ DON'T DO THIS if (element.getAttribute('readonly')) { console.log('✅ element is readonly'); } else { console.log('⛔️ element is not readonly'); }
Note that the attribute name is spelled in all lowercase, however when accessing the property on the element, it is in camel case - readOnly.

The getAttribute method returns the value of the provided attribute on the element.

However, it's a best practice to set boolean attributes, such as readonly, without a value.

If a boolean attribute is present at all, regardless of the value, its value is considered to be true.

If a boolean attribute is not present, the value of the attribute is considered to be false.

Therefore the readonly attribute could be set without a value on the element and the getAttribute method would return a false negative.

If you need to remove the readonly attribute from an element, use the removeAttribute() method.

index.js
const element = document.getElementById('first_name'); element.removeAttribute('readonly');

The removeAttribute method removes the provided attribute from the element.

If the attribute does not exist on the element, the method returns without throwing an error.

If you need to set the readonly attribute on an element, use the setAttribute() method.

index.js
const element = document.getElementById('first_name'); element.setAttribute('readonly', '');

The method takes the following 2 parameters:

  1. name - the name of the attribute to be set.
  2. value- the value to assign to the attribute.
We provided an empty string as the value for the readonly attribute because it's a best practice to set boolean attributes without a value.
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