please check plugin code in firebug and wp-debug mode

mutating the Prototype of an object will cause your code to run very slowly; instead create the object with the correct initial Prototype value using Object.create
xregexp.js:1:222

occurs on normal pages
post.php?post=3398&action=edit
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may also ad options to hide squirrly on Woocommece product pages, or other pages with no SEO relevat content.

https://wordpress.org/plugins/squirrly-seo/