nav-up property is for navigating with directional navigation keys (such as the "up" arrow on the keyboard).
The property determines where the focus will be placed when the user navigates with the up arrow (or other navigational key).
Most desktop computers and laptops have keyboards that contain four arrow keys. Whilst these are good candidates for the
nav-* properties, user agents could also make this configurable so that the user decides which keys will be used for directional navigation.
At the time of writing, the
nav-up property has almost no support from the major browsers.
Here are the possible values:
- The browser/user agent determines which element to navigate the focus to.
- Specifies the ID selector of an element to navigate to. When the user navigates, the focus is changed to the first element in the document tree with this ID.
- Specifies the target frame to navigate to. Must be a string but it must not start with an underscore "_" character.
In addition, all CSS properties also accept the following CSS-wide keyword values as the sole component of their property value:
- Represents the value specified as the property's initial value.
- Represents the computed value of the property on the element's parent.
- This value acts as either
initial, depending on whether the property is inherited or not. In other words, it sets all properties to their parent value if they are inheritable or to their initial value if not inheritable.
Basic Property Information
- Initial Value
- Applies To
- All enabled elements.
Working Example within an HTML Document
nav-upproperty is defined in CSS Basic User Interface Module Level 3 (CSS3 UI) (W3C Candidate Recommendation, 7 July 2015).
For maximum browser compatibility many web developers add browser-specific properties by using extensions such as
-webkit- for Safari, Google Chrome, and Opera (newer versions),
-ms- for Internet Explorer,
-moz- for Firefox,
-o- for older versions of Opera etc. As with any CSS property, if a browser doesn't support a proprietary extension, it will simply ignore it.
This practice is not recommended by the W3C, however in many cases, the only way you can test a property is to include the CSS extension that is compatible with your browser.
The major browser manufacturers generally strive to adhere to the W3C specifications, and when they support a non-prefixed property, they typically remove the prefixed version. Also, W3C advises vendors to remove their prefixes for properties that reach Candidate Recommendation status.
Many developers use Autoprefixer, which is a postprocessor for CSS. Autoprefixer automatically adds vendor prefixes to your CSS so that you don't need to. It also removes old, unnecessary prefixes from your CSS.
You can also use Autoprefixer with preprocessors such as Less and Sass.