ref: cb39847dee488c373dd5bc2a3706385342a59355
dir: /content/en/functions/safeURL.md/
---
title: safeURL
description: Declares the provided string as a safe URL or URL substring.
godocref: https://golang.org/pkg/html/template/#HTMLEscape
date: 2017-02-01
publishdate: 2017-02-01
lastmod: 2017-02-01
keywords: [strings,urls]
categories: [functions]
menu:
docs:
parent: "functions"
signature: ["safeURL INPUT"]
workson: []
hugoversion:
relatedfuncs: []
deprecated: false
aliases: []
---
`safeURL` declares the provided string as a "safe" URL or URL substring (see [RFC 3986][]). A URL like `javascript:checkThatFormNotEditedBeforeLeavingPage()` from a trusted source should go in the page, but by default dynamic `javascript:` URLs are filtered out since they are a frequently exploited injection vector.
Without `safeURL`, only the URI schemes `http:`, `https:` and `mailto:` are considered safe by Go templates. If any other URI schemes (e.g., `irc:` and `javascript:`) are detected, the whole URL will be replaced with `#ZgotmplZ`. This is to "defang" any potential attack in the URL by rendering it useless.
The following examples use a [site `config.toml`][configuration] with the following [menu entry][menus]:
{{< code file="config.toml" copy="false" >}}
[[menu.main]]
name = "IRC: #golang at freenode"
url = "irc://irc.freenode.net/#golang"
{{< /code >}}
The following is an example of a sidebar partial that may be used in conjunction with the preceding front matter example:
{{< code file="layouts/partials/bad-url-sidebar-menu.html" copy="false" >}}
<!-- This unordered list may be part of a sidebar menu -->
<ul>
{{ range .Site.Menus.main }}
<li><a href="{{ .URL }}">{{ .Name }}</a></li>
{{ end }}
</ul>
{{< /code >}}
This partial would produce the following HTML output:
{{< output file="bad-url-sidebar-menu-output.html" >}}
<!-- This unordered list may be part of a sidebar menu -->
<ul>
<li><a href="#ZgotmplZ">IRC: #golang at freenode</a></li>
</ul>
{{< /output >}}
The odd output can be remedied by adding ` | safeURL` to our `.URL` page variable:
{{< code file="layouts/partials/correct-url-sidebar-menu.html" copy="false" >}}
<!-- This unordered list may be part of a sidebar menu -->
<ul>
<li><a href="{{ .URL | safeURL }}">{{ .Name }}</a></li>
</ul>
{{< /code >}}
With the `.URL` page variable piped through `safeURL`, we get the desired output:
{{< output file="correct-url-sidebar-menu-output.html" >}}
<ul class="sidebar-menu">
<li><a href="irc://irc.freenode.net/#golang">IRC: #golang at freenode</a></li>
</ul>
{{< /output >}}
[configuration]: /getting-started/configuration/
[menus]: /content-management/menus/
[RFC 3986]: https://tools.ietf.org/html/rfc3986