Go step by step and test.

WebKit CSS extensions. Applications based on WebKit or Blink, such as Safari and Chrome, support a number of special WebKit extensions to CSS. These extensions are generally prefixed with -webkit. Most -webkit- prefixed properties also work with an -apple- prefix. A few are prefixed with -epub. Display web content in windows and implement browser features using WebKit. WebKit Documentation. Mac mini (Late 2012), OS X Mavericks (10.9.2), 2.3 GHz i7; 16GB, 1TB HD.

1. Empty Caches

Safari > Preference > Advanced

Checkmark the box for 'Show Develop menu in menu bar'.

Develop menu will appear in the Safari menu bar.

Click Develop and select 'Empty Caches' from the dropdown.

2. Delete Cookies

Webkit Browser

Safari > Preferences > Privacy > Cookies and other website data:

Click “Remove All Website Data”.

3. Safari > Preferences > Extensions

Webkit2

Turn off Extensions if any and launch Safari again to test.

Turn on those one by one and test.

Webkit-scrollbar

Jan 21, 2015 3:10 AM