With kses filtering, WordPress only allows a subset of html tags within a post or page, and one of the tags it strips out is the <iframe> tag (for many good reasons).

I'd like to allow editors to include iframes where the src is from one of our other subdomains, or from a specified whitelist of domains, but still strip out other unknown src's. It is straightforward to bypass kses to allow all <iframe>'s, but is it possible to only allow certain domains?

  • What do you think about making it with shortcodes? Take a look at this plugin wordpress.org/plugins/iframe. Find there shortcode process function and add validation for domain with parse_url function. If this solution is good for you, I can help to write the function Commented Aug 23, 2017 at 18:27
  • Thats a great idea! I got caught up looking up wp-kses options and didn't even consider a shortcode. Perfect. Thanks!
    – joetek
    Commented Aug 23, 2017 at 18:55

1 Answer 1


I'd register an embed handler with wp_embed_register_handler. This gives you the added benefit of being able to just copy and paste the url into the editor as well as seeing a preview of the iframe.

add_action( 'init', 'se238330_register_embed_handler' );

function se238330_register_embed_handler() {

function wp_embed_handler_embed_name( $matches, $attr, $url, $rawattr ) {
    $embed = sprintf(
        '<iframe class="joetek-website" src="http://subdomain.yourdomain.com/%1$s/" width="600" height="400" frameborder="0" scrolling="no"></iframe>',
        esc_attr( $matches[1] )

    return apply_filters( 'embed_joetek', $embed, $matches, $attr, $url, $rawattr );

The code above assumes that joetek is the name of your embed :) You'd need to update the regex in the second parameter of wp_embed_register_handler as well as in the callback function to match the pages you want to be able to embed on your website.

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