HTML Guides for browsing context

The target attribute specifies where a linked document should be opened. When the validator encounters target="", it reports an error because the HTML specification requires browsing context names to be at least one character long. An empty string is not a valid browsing context name and has no defined behavior, which means browsers may handle it inconsistently.

This issue commonly arises when a target value is dynamically generated by a CMS, template engine, or JavaScript and the value ends up being empty. It can also happen when a developer adds the attribute with the intent to fill it in later but forgets to do so.

Setting target to an empty string is problematic for several reasons:

• Standards compliance: The WHATWG HTML specification explicitly requires valid browsing context names to be non-empty strings. An empty value violates this rule.
• Unpredictable behavior: Browsers may interpret an empty target differently — some may treat it like _self, others may behave unexpectedly. This makes your site harder to test and maintain.
• Accessibility concerns: Screen readers and assistive technologies may announce the target attribute or use it to inform users about link behavior. An empty value provides no meaningful information.

To fix this, choose one of the following approaches:

1. Remove the attribute if you want the default behavior (opening in the same browsing context, equivalent to _self).
2. Set a valid keyword like _blank, _self, _parent, or _top.
3. Set a custom name if you want multiple links to share the same browsing context (e.g., target="externalWindow").

Examples

❌ Invalid: empty target attribute

<a href="https://example.com" target="">Visit Example</a>

This triggers the validation error because the target value is an empty string.

✅ Fixed: remove target entirely

If you want the link to open in the current browsing context (the default), simply remove the attribute:

<a href="https://example.com">Visit Example</a>

✅ Fixed: use _blank to open in a new tab

<a href="https://example.com" target="_blank" rel="noopener">Visit Example</a>

Note the addition of rel="noopener" — this is a security best practice when using target="_blank", as it prevents the opened page from accessing the window.opener property.

✅ Fixed: use _self explicitly

If you want to be explicit about opening in the same context:

<a href="https://example.com" target="_self">Visit Example</a>

✅ Fixed: use a custom browsing context name

You can use a custom name so that multiple links reuse the same tab or window:

<a href="https://example.com" target="externalWindow">Example</a>
<a href="https://example.org" target="externalWindow">Example Org</a>

Both links will open in the same browsing context named externalWindow. If it doesn’t exist yet, the browser creates it; subsequent clicks reuse it.

Dynamic templates

If your target value comes from a template or CMS, make sure the attribute is conditionally rendered rather than output with an empty value. For example, in a templating language:

<!-- Instead of always outputting target -->

<a href="https://example.com" target="">Visit</a>

<!-- Only include target when a value exists -->

<a href="https://example.com" target="_blank" rel="noopener">Visit</a>

In your template logic, conditionally omit the target attribute entirely when no value is provided, rather than rendering it as an empty string.

In HTML, the name attribute on an <iframe> defines a browsing context name. This name can be referenced by other elements — for example, a link with target="my-frame" will open its URL inside the <iframe> whose name is "my-frame". The HTML specification reserves all browsing context names that start with an underscore for special keywords:

• _self — the current browsing context
• _blank — a new browsing context
• _parent — the parent browsing context
• _top — the topmost browsing context

Because the underscore prefix is reserved for these (and potentially future) keywords, the spec requires that any custom browsing context name must not begin with _. Setting name="_example" or name="_myFrame" on an <iframe> is invalid HTML, even though those exact strings aren’t currently defined keywords. Browsers may handle these inconsistently — some might ignore the name entirely, while others could treat it as one of the reserved keywords, leading to unexpected navigation behavior.

This matters for several reasons:

• Standards compliance: The WHATWG HTML living standard explicitly states that a valid browsing context name must not start with an underscore character.
• Predictable behavior: Using a reserved prefix can cause links or forms targeting that <iframe> to navigate in unintended ways (e.g., opening in a new tab instead of within the frame).
• Future-proofing: New underscore-prefixed keywords could be added to the spec, which might break pages that use custom names starting with _.

To fix the issue, simply rename the name attribute value so it doesn’t start with an underscore. You can use underscores elsewhere in the name — just not as the first character.

Examples

❌ Invalid: name starts with an underscore

<iframe src="https://example.com" name="_example"></iframe>

<a href="https://example.com/page" target="_example">Open in frame</a>

The name _example starts with an underscore, which makes it invalid. A browser might interpret _example unpredictably or ignore the name entirely when used as a target.

✅ Fixed: underscore removed from the start

<iframe src="https://example.com" name="example"></iframe>

<a href="https://example.com/page" target="example">Open in frame</a>

✅ Fixed: underscore used elsewhere in the name

<iframe src="https://example.com" name="my_example"></iframe>

<a href="https://example.com/page" target="my_example">Open in frame</a>

Underscores are perfectly fine as long as they aren’t the first character.

❌ Invalid: using a reserved keyword as a frame name

<iframe src="https://example.com" name="_blank"></iframe>

Using _blank as an <iframe> name is also invalid because it’s a reserved browsing context keyword. A link targeting _blank would open in a new window/tab rather than inside this <iframe>, which is almost certainly not what you intended.

✅ Fixed: descriptive name without underscore prefix

<iframe src="https://example.com" name="content-frame"></iframe>

<a href="https://example.com/page" target="content-frame">Open in frame</a>

How to fix

1. Find every <iframe> element whose name attribute starts with _.
2. Rename each one by removing the leading underscore or replacing it with a letter or other valid character.
3. Update any target attributes on <a>, <form>, or <base> elements that reference the old name so they match the new name.
4. Re-validate your HTML to confirm the issue is resolved.