Uncaught TypeError: Cannot read property 'replace' of undefined
Caused by:
overridableFontFamilies = $.map( overridableFontFamilies, function( item ) { return item.replace( /[\s'"]/g, '' ); } );
item is undefined because overridableFontFamilies contains undefined. It contains undefined because of:
overridableFontFamilies: [ $( 'h1' ).css( 'font-family' ) ]
This particular page does not have h1 element, so the call returns undefined.
Version: master
Severity: normal