Any standard for Unicode font support expected of all browsers?
cross-browser, fonts, standards, unicode
Solution
There is no standard on Unicode support in browsers. Besides, the ability to display a character mostly depends on fonts, though browsers differ in their abilities in scanning through fonts. Normally what you can do is to specify a suitable `font-family` list of fonts that each support all the characters you need. For generalities on this, see my Guide to using special characters in HTML.
On Android, the problem is that there is a very limited set of fonts. If you need any characters beyond what is supported by them, you need to use a downloadable font, via `@font-face`.
The currency symbol “؋” U+060B AFGHANI SIGN is present in about a dozen fonts, but the only free font among them (if we don’t count the bitmap font GNU Unifont) appears to be Scheherazade.
For U+202F NARROW NO-BREAK SPACE, font support is wider. But in general, it is often better to use other methods than such characters. Many fonts contain this character as almost as wide as a normal space, and its description in the Unicode standard as regards to its width is vague: “a narrow form of a no-break space, typically the width of a thin space or a mid space”. “Thin space” is described as “a fifth of an em (or sometimes a sixth)” in the Unicode standard, and in reality its width varies. And “mid space” is really an undefined concept.
For example, if the text is in a language that uses spaces as thousands separators, you could in principle write a number like 100 000 as `100 000`, but it’s better to write, say,
<span class="gr">100 000</span>
with CSS code like `.gr { word-spacing: -0.15em }`.
Problem
Is there a standard governing Unicode font support expected of all browsers? The latest version of Unicode contains a repertoire of more than 110,000 characters covering 100 scripts. I don't expect the browsers to support all of them, but there should be minimum support for some characters such as letters from the Latin script, common punctuation, and symbols of type math, currency, and other. I am currently having problem displaying the U+060B AFGANI SIGN (؋) and U+202F NARROW NON-BREAK SPACE on the Android browser. I wonder if there is a list of universally recognized Unicode characters so that developers can use them confidently without having to worry about browser display issues.