WordPress.org

How can I exclude categories?

List its ID as a negative number.

My site broke after customizing the excerpt. What happened?

Did you set the strip_tags attribute to false? ([excerpt strip_tags=0]). If tags haven't been stripped, it may have cut off the text before an HTML tag was properly closed, thus breaking the page. Setting strip_tags to false should only be used if you're carefully managing the excerpt's output.

Why can't I add an ID to the element in 'Before Items'?

There are limitations on the tag or tag/attribute combiniations allowed by WordPress. However, these can be overcome with a few lines of code.

To allow an additional tag, use this:

add_filter( "admin_init", "allowed_tags" );
function allowed_tags() {
    global $allowedposttags;
    $allowedposttags["video"] = array();
}

To allow additional attributes for any tag, use the following code:

add_filter( "admin_init", "allowed_tags" );
function allowed_tags() {
    global $allowedposttags;
    $allowedposttags["video"]["src"] = array();
    $allowedposttags["video"]["type"] = array();
    $allowedposttags["video"]["poster"] = array();
}

If you're using a custom theme, you can add this code the its functions.php file. Otherwise, you may want to create your own plugin to hold these modifications.

See this post for instructions on creating your own plugin.