farinspace

HiFi is a head injection and foot injection plugin (or head include, foot include, head insert, foot insert, what ever you want to call it). It basically allows you to inject <code><script></code>, <code><style></code>, <code><meta></code> and any other code you want into the head and foot areas of your posts and pages. The code injected is page-specific, this means that only the pages you want code inserted into will be affected.
This plugin is most useful when you have specific functionality that needs to be added on a per-post/page basis.

HiFi (Head Injection, Foot Injection)

HiFi is a head and foot injection plugin. It allows you to inject code into the head and foot areas of your posts and pages on a per-page basis.

iliasvlachos1

This plugin is usefull to website owners who share links from their website on Facebook. If you debug your website URL with the <a href="https://developers.facebook.com/tools/debug/" rel="nofollow ugc">Facebook Sharing Debugger</a> you might see a warning with the following message.
Missing Properties: The following required properties are missing: fb:app_id
This plugin inserts the required meta property with the given app_id. You have to create a facebook app to get the app_id!
To create a facebook app, visit <a href="https://developers.facebook.com/" rel="nofollow ugc">Facebook Developers</a>
<ol>
<li>Register or Login to your account.</li>
<li>Click My Apps, then click Create to create a new App</li>
<li>When the app is created and you are in the app dashboard click settings and select Basic</li>
</ol>
That is the App ID you need to copy.
On your WordPress Admin:
<ol>
<li>Download and activate the plugin</li>
<li>Go to Tools -> Fix missing FB app_id.</li>
<li>Paste the app_id you copied in the given field.</li>
<li>Click Save</li>
</ol>

Fix missing property app_id

This plugin inserts the fb:app_id meta property to fix the Facebook Sharing Debugger error «The following required properties are missing: fb:app_id»

HiFi (Head Injection, Foot Injection) vs Fix missing property app_id