The <url>
CSS data type denotes a pointer to a resource, such as an image or a font. URLs can be used in numerous CSS properties, such as background-image
, cursor
, and list-style
.
URI or URL? There is a difference between a URI and a URL. A URI simply identifies a resource. A URL is a type of URI, and describes the location of a resource. A URI can be either a URL or a name (URN) of a resource.
In CSS Level 1, the url()
functional notation described only true URLs. In CSS Level 2, the definition of url()
was extended to describe any URI, whether a URL or a URN. Confusingly, this meant that url()
could be used to create a <uri>
CSS data type. This change was not only awkward but, debatably, unnecessary, since URNs are almost never used in actual CSS. To alleviate the confusion, CSS Level 3 returned to the narrower, initial definition. Now, url()
denotes only true <url>
s.
Syntax
The <url>
data type is specified using the url()
functional notation. It may be written without quotes, or surrounded by single or double quotes. Relative URLs are allowed, and are relative to the URL of the stylesheet (not to the URL of the web page).
If you choose to write the URL without quotes, use a backslash (\) before any parentheses, whitespace characters, single quotes (') and double quotes (") that are part of the URL.
<a_css_property>: url("http://mysite.example.com/mycursor.png") <a_css_property>: url('http://mysite.example.com/mycursor.png') <a_css_property>: url(http://mysite.example.com/mycursor.png)
Examples
.topbanner { background: url("topbanner.png") #00D no-repeat fixed; }
ul { list-style: square url(http://www.example.com/redball.png); }
Specifications
Specification | Status | Comment |
---|---|---|
CSS Values and Units Module Level 4 The definition of '<url>' in that specification. |
Editor's Draft | |
CSS Values and Units Module Level 3 The definition of '<url>' in that specification. |
Candidate Recommendation | No significant change from CSS Level 2 (Revision 1). |
CSS Level 2 (Revision 1) The definition of '<uri>' in that specification. |
Recommendation | No significant change from CSS Level 1. |
CSS Level 1 The definition of '<url>' in that specification. |
Recommendation | Initial definition. |
Browser compatibility
Desktop | Mobile | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
<url> | Chrome Full support 1 | Edge Full support 12 | Firefox Full support 1 | IE Full support 3 | Opera Full support 3.5 | Safari Full support 1 | WebView Android Full support 1 | Chrome Android Full support 18 | Firefox Android Full support 4 | Opera Android Full support 14 | Safari iOS Full support 1 | Samsung Internet Android Full support 1.0 |
Legend
- Full support
- Full support