A simple reduction from the Letter of Damar Wulan on http://www.wdl.org/en/item/14282/ using Microsoft's Javanese Text font and the Tuladha Jejeg webfont. The underlying cause of the problem is that operating systems other Windows 8.1 do not ship a font with Javanese support and the script requires complex text formatting which isn't consistently available. Firefox has support for SIL's Graphite and consistently looks correct on every platform. Chrome looks good on Windows 7+ but not OS X. Safari is incorrect on OS X 10.9.

Reviewer comments on browser support

How this displays on your browser

ꦱꦼꦫꦠ꧀ ꦢꦩꦂꦮꦸꦭꦤ꧀

Reference image (Firefox 31 on OS X 10.9)