--- /dev/null
+# function-url-no-scheme-relative
+
+Disallow scheme-relative urls.
+
+```css
+a { background-image: url('//www.google.com/file.jpg'); }
+/** ↑
+ * This scheme-relative url */
+```
+
+A [scheme-relative url](https://url.spec.whatwg.org/#syntax-url-scheme-relative) is a url that begins with `//` followed by a host.
+
+This rule ignores url arguments that are variables (`$sass`, `@less`, `--custom-property`).
+
+## Options
+
+### `true`
+
+The following patterns are considered violations:
+
+```css
+a {
+ background: url("//www.google.com/file.jpg");
+}
+```
+
+The following patterns are *not* considered violations:
+
+```css
+a {
+ background: url("../file.jpg");
+}
+```
+
+```css
+a {
+ background: url("http://www.google.com/file.jpg");
+}
+```
+
+```css
+a {
+ background: url("/path/to/file.jpg");
+}
+```