HTML Guides for rows

The <textarea> element represents a multi-line plain-text editing control, commonly used for comments, feedback forms, and other free-form text input. The rows attribute specifies the number of visible text lines the textarea should display. According to the HTML specification, when the rows attribute is present, its value must be a valid positive integer — meaning a string of one or more digits representing a number greater than zero (e.g., 1, 5, 20). An empty string ("") does not meet this requirement.

This issue typically occurs when a template engine, CMS, or JavaScript framework dynamically sets the rows attribute but outputs an empty value instead of a number, or when a developer adds the attribute as a placeholder intending to fill it in later.

Why this matters

• Standards compliance: The HTML specification explicitly requires rows to be a positive integer when present. An empty string violates this rule.
• Unpredictable rendering: Browsers fall back to a default value (typically 2) when they encounter an invalid rows value, but this behavior isn’t guaranteed to be consistent across all browsers and versions.
• Maintainability: Invalid attributes can mask bugs in dynamic code that was supposed to provide a real value.

How to fix it

You have two options:

1. Set a valid positive integer: Replace the empty string with a number like 4, 5, or whatever suits your design.
2. Remove the attribute: If you don’t need to control the number of visible rows (or prefer to handle sizing with CSS), simply omit the rows attribute. The browser will use its default.

If the value is generated dynamically, ensure your code has a fallback so it never outputs an empty string. You can also control the textarea’s height using CSS (height or min-height) instead of relying on the rows attribute.

Examples

❌ Invalid: empty string for rows

<textarea name="comments" rows="" cols="25">
</textarea>

This triggers the error because "" is not a valid positive integer.

✅ Fixed: providing a valid positive integer

<textarea name="comments" rows="5" cols="25">
</textarea>

Setting rows="5" tells the browser to display five visible lines of text.

✅ Fixed: removing the attribute entirely

<textarea name="comments" cols="25">
</textarea>

When rows is omitted, the browser uses its default (typically 2 rows). This is perfectly valid.

✅ Alternative: using CSS for sizing

<textarea name="comments" style="height: 10em; width: 25ch;">
</textarea>

If you need precise control over the textarea’s dimensions, CSS properties like height, min-height, and width give you more flexibility than the rows and cols attributes. In this case, you can safely leave both attributes off.