When faced with the challenge of dealing with extended ASCII characters in font files, sometimes there is no easy or clean solution aside from remodeling the fonts themselves. Here is a handy JavaScript snippet that can help replace these characters with a <span>
element. (You may find yourself asking the same question again if you come across unsupported characters by accident.)
Using JS on sample text:
"Hêllo wörld. ÄÖÜßäöü".replace(/([\x80-\xff])/gi, '<span class="arial">$&</span>')
Result:
H<span class="arial">ê</span>llo w<span class="arial">ö</span>rld. <span class="arial">Ä</span><span class="arial">Ö</span><span class="arial">Ü</span><span class="arial">ß</span><span class="arial">ä</span><span class="arial">ö</span><span class="arial">ü</span>
For jQuery:
$('.webfont').each(function(){
this.innerHTML = this.innerHTML.replace(/([\x80-\xff])/gi, '<span class="arial">$&</span>')
});
The elements with the class .webfont
should ideally only contain text for this to work seamlessly, though it may also function in other scenarios.