Control User Input
Mastering the HTML maxlength Attribute

What is The HTML maxlength Attribute?

The maxlength attribute in HTML is a crucial tool for controlling the length of text entered into and </code> elements. It specifies the maximum number of UTF-16 code units that a user can input.</p><p class="text-neutral-700 leading-relaxed mb-6 text-lg ">Understanding <code>maxlength</code> helps you create more robust and user-friendly forms, ensuring data integrity and a better overall experience. This attribute is especially important when dealing with databases or APIs that have character limits.</p></section><section data-section-id="usage"><h2 id="usage" class="text-3xl lg:text-4xl font-bold text-primary mb-8 leading-tight"><span class="bg-gradient-to-r from-indigo-500 via-purple-500 to-pink-500 bg-clip-text text-transparent">Implementing</span> <!-- -->How to Use the maxlength Attribute</h2><p class="text-neutral-700 leading-relaxed mb-6 text-lg font-medium">To use the <code>maxlength</code> attribute, simply add it to your <code><input></code> or <code><textarea></code> tag, setting its value to a positive integer representing the maximum allowed length. For example: <code><input type="text" maxlength="50"></code> or <code><textarea maxlength="200">.

If no maxlength is specified, or if an invalid value (e.g., a non-integer or a negative number) is provided, the input field has no maximum length.

Remember that the length is measured in UTF-16 code units. This is often, but not always, the same as the number of characters. Be mindful of this when dealing with multi-byte characters.

Constraint maxlength and Validation

The maxlength attribute plays a significant role in constraint validation. The input element will fail constraint validation if the length of the text value exceeds the specified maxlength.

While browsers generally prevent users from entering more text than maxlength allows, it's crucial to validate the data on the server-side to ensure security and data integrity. The read-only property of an object will be true if the input is longer than allowed.

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Using the maxlength attribute is fundamental to a smooth user experience.

The Content Alchemist

Practical Examples of maxlength in Action

Here are some examples demonstrating how to use the maxlength attribute:

`html Username (max 20 characters): `

`html Comment (max 100 characters): `

Browser Compatibility

The maxlength attribute is widely supported across all modern web browsers, ensuring consistent behavior across different platforms. The provided examples and specifications showcase its broad availability.

Refer to resources such as MDN Web Docs to verify exact browser compatibility for specific versions and edge cases.