Enter: data:text/html,<div%20style="border-image-source:%20linear-gradient(-45deg,%20red,%20currentcolor)"> Then window.getComputedStyle(document.getElementsByTagName('div')[0]).borderImageSource it returns red and currentcolor for Safari while it returns the rgb value for Firefox and Chrome.
<rdar://problem/99420904>
*** This bug has been marked as a duplicate of bug 246927 ***
WebKit now returns "linear-gradient(-45deg, rgb(255, 0, 0), rgb(0, 0, 0))"