<commit_before>project_path: /web/tools/_project.yaml
book_path: /web/tools/_book.yaml
description: Reference documentation for the "Opens External Anchors Using rel="noopener"" Lighthouse audit.

{# wf_updated_on: 2017-12-11 #}
{# wf_published_on: 2016-11-30 #}
{# wf_blink_components: N/A #}

# Opens External Anchors Using rel="noopener"  {: .page-title }

## Overview {: #overview }

When your page links to another page using `target="_blank"`, the new page
runs on the same process as your page. If the new page is executing expensive
JavaScript, your page's performance may also suffer.

On top of this, `target="_blank"` is also a security vulnerability. The new page
has access to your window object via `window.opener`, and it can navigate your
page to a different URL using `window.opener.location = newURL`.

See [The Performance Benefits of rel=noopener][jake] for more information.

[jake]: https://jakearchibald.com/2016/performance-benefits-of-rel-noopener/

## Recommendations {: #recommendations }<commit_msg>Link to explanation of the rel=noopener security issue (#5663)<commit_after>project_path: /web/tools/_project.yaml
book_path: /web/tools/_book.yaml
description: Reference documentation for the "Opens External Anchors Using rel="noopener"" Lighthouse audit.

{# wf_updated_on: 2017-12-11 #}
{# wf_published_on: 2016-11-30 #}
{# wf_blink_components: N/A #}

# Opens External Anchors Using rel="noopener"  {: .page-title }

## Overview {: #overview }

When your page links to another page using `target="_blank"`, the new page
runs on the same process as your page. If the new page is executing expensive
JavaScript, your page's performance may also suffer. See [The Performance
Benefits of `rel=noopener`][jake] for more information.


On top of this, `target="_blank"` is also a security vulnerability. The new page
has access to your `window` object via `window.opener`, and it can navigate your
page to a different URL using `window.opener.location = newURL`. See [About
`rel=noopener`][mths] for a demo and explanation of the vulnerability.

[jake]: https://jakearchibald.com/2016/performance-benefits-of-rel-noopener/
[mths]: https://mathiasbynens.github.io/rel-noopener/

## Recommendations {: #recommendations }
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