2 回答
The character is definitely not everyday-use. If your phone doesn't show it, it means just that nobody got around to add it to the font in use.
The Wikipedia page Interrobang you refer to says, “few modern typefaces or fonts include a glyph for the interrobang character”. That’s inaccurate – e.g., on a PC, there’s normally at least the Palatino Linotype font containing it, and in modern PCs, the so-called Microsoft C fonts contain it, too (see Fileformat.info page on font coverage). But e.g. in Android, there is normally just the Droid collection of fonts, and they don’t have this symbol.
So using a downloadable font (web font) via @font-face would be the only way to make e.g. Androids display this character (except on those ’droids that have suitable extra font installed by user, but these are not the ’droids you are looking for).
However, apart from using an image, there’s also the workaround of using the “?” and “!” characters somehow superimposed. You could achieve this e.g. by using negative letter-spacing or setting a negative margin on a character wrapped in an element declared to be an inline block. But probably the best shot is to use positioning:
<style>
.bang { position: relative; }
.excl { position: absolute; left: 0.1em; }
</style>
<span class=bang>?<span class=excl>!</span></span>
The value of 0.1em is a guess, but probably a fairly good one. The point is that the advance width of “!” is smaller than that of “?”, in most fonts, so it needs to be pushed a bit to the left in order to “overstrike” the question mark suitably. This value seems to work both for Droid Sans and for Arial.