I am aware that any Unicode character can be inserted into an HTML document via the following format:
...where 0000 is the character code of the desired character
My question is: which of these characters has the most widespread availability when it comes to the client's browser being able to display the character?
In other words, what are the ranges of codes that should be used in an HTML document that is going to be widely deployed?
Whether you enter them via &#xNNNN; character reference or just by typing or copy-pasting them directly into the page, it's purely a question of fonts. If the user has a glyph for the character in the fonts their web browser knows about, it'll work. If they don't, it'll be a little box.
fileformat.info have font-availability details that can be of help for guessing how widespread glyph support is. eg. hit the Fonts link on this page for U+25B6. For me, this renders on most platforms but not on a vanilla XP install with IE6 (IE7 picks it up from Lucida Sans Unicode which IE6 FSR doesn't bother look at).
◄ ► U+25C4, U+25BA Left/Right-Pointing Pointer glyphs seem to be more widely available than
◀ ▶ U+25C0, U+25B6 Left/Right-Pointing Triangle glyphs
so I'd use those instead. In particlar they render in XP+IE6 with default fonts because they are present in Arial. Which renders them more like Triangle than Pointer is supposed to be. (sigh) OTOH its up/down Triangles are fine.
SO uses ► for list bullets in the ‘how to format’ box over there. ⇗
[response to comment in edit instead of comment as site JS appears to be playing up]
There's also ‣, U+2023 Triangular Bullet, which is in a block of widely-available typographical-niceties. Unfortunately, again, it's not in Arial or other fonts IE6 on a default XP will use. Neither is ▸ U+25B8 Black Right-Pointing Small Triangle.
French-style quotes (guillemets) ‹ › « » will be available absolutely everywhere, but using them for arrows might be considered a bit of an abuse.
Related
I'm trying to figure out why characters like this : 👉 show up like empty boxes. They are unicode characters though and charset is utf-8.
Can it be a font problem which doesn't have a glyph for that? Any ideas?
Details: Html page, i use firefox 16.0.1, Windows 7.. Page like on this post i dont see this glyph either
Thanks
The character which you've there is the Unicode Character 'WHITE RIGHT POINTING BACKHAND INDEX' (U+1F449). On that page, you can find a list of known fonts supporting the character behind the link Fonts that support U+1F449.
Font
LastResort
Segoe UI Emoji
Segoe UI Symbol
Symbola
Neither of those fonts is been used here on stackoverflow.com, so you'll also see an empty box.
If this occurs on your own website, and you'd like to fix it, then you'd need to supply a supporting font along with the webapp by CSS #font-face, or in this particular case perhaps better, look for a CSS based icon library such as Font Awesome. The <i class="fa fa-hand-o-right"> comes very close with this character.
The character U+1F449 was added to Unicode in version 6 in 2010, and it generally takes about ten years from the adoption of a character into Unicode before it is widely supported in fonts.
The few fonts that contain it now include Symbola and Segoe UI Symbol. If you have either of them installed, you’ll probably see it; otherwise not. Segoe UI Symbol is shipped with Windows 8 and apparently with (at least some variants of) Windows 7, though the Windows 7 version may be limited – an update is available from Microsoft. Symbola is a free font, so you could in principle use it as a downloadable font (via #font-face), but its file size is rather large.
Web browsers are supposed to use fallback fonts, if the fonts specified for an element do not contain a glyph for some character in the content. Firefox generally implements this will, IE does not, especially in older versions, so if you use the character on a web page, it is best to wrap in an element of its own (usually span is used for the purpose) and set the following on it in CSS:
font-family: Segoe UI Symbol, Symbola;
But this will as such (without #font-face) work only for people using computers that contain one of the fonts.
Missing font characters will usually be substituted with other fonts, and UTF-8 should be able to display all unicode characters. I suspect that the encoding of your file (how it is saved by your editor), does not match the declaration in the meta tags of your HTML page.
You can check your page with this W3-checker, it can possibly give you hints about the problem of your page.
EDIT:
You are right, it's not an encoding problem, the number of the character has such a high number, that the "normal" fonts do not support it. Maybe you can use one of those ☛ ☞, otherwise you would have to use a web font, and fonts with full unicode support can be quite large.
i want to design my own video player. I want to add this special character as a "volume"-button: 🔉 http://www.fileformat.info/info/unicode/char/1f509/index.htm. But it always shows a weird rectangle with the number 01F509.
Whats wrong ?
greetings
When you see a weird rectangle with the number 01F509, it means that the browser has correctly recognized the character but cannot display it due to lack of glyph for it. Either the system has no font containing a glyph for the character, or the character is unable to use such a font, due to a browser bug. For generalities, see my Guide to using special characters in HTML.
The Fileformat.info page cited has a link to a list of fonts that support the character. The list is short: Quivira, Segoe UI Emoji, Segoe UI Symbol, Symbola. (LastResort is not a real font.)
Segoe UI fonts are proprietary and available only in relatively new versions of Windows. Besides, there fonts exist in several version, and this character seems to be a rather recent addition.
This means that you wold need to use Quivira or Symbola as a web font (downloadable font). If you choose to do that, use e.g. http://www.fontsquirrel.com/ to generate the font files and the CSS code for using them. Note that both Quivira and Symbola rather large fonts, so using them just to get one glyph is a bit disproportionate.
At this point, it is rather obvious that some other approach is most probably better, e.g. using an image in sufficient size and reducing it according to font size by setting its height in em units.
To avoid encoding issues, try including the character in your HTML code using the hexadecimal entity notation: 🔉 then make sure that the font you are using contains this character, else you'll see a rectangle in place of the character.
You may create your own font with the desired character using tools such as http://icomoon.io
Also note that some browsers have issues displaying characters outside of the range 0000 to FFFF (plane 0 of the Basic Multilingual Plane (BMP)). I have experienced the issue with Safari on Windows and IE <= 8. So try avoiding this range if you want to support all browsers.
HTML entities are not working on chrome and IE (on windows).
I have entered the following code in my page and it works fine on mac chrome or firefox or safari, but not on windows.
<span class="font-family:Arial;">〈 〉 〉 〈 </span>
This is primarily a font issue, though there is a nasty silent change in HTML specs involved.
Modern browsers interpret 〈 and 〉 as referring to U+27E8 MATHEMATICAL LEFT ANGLE BRACKET “⟨” and U+27E9 MATHEMATICAL RIGHT ANGLE BRACKET “⟩”, informally known as “bra” and “ket”. This interpretation is being made official in the named character references section of HTML5.
These characters are adequate for use in many mathematical notations, and the ISO 80000-2 standard explicitly specifies that they are used e.g. for certain scalar product notations. But support to them in fonts is rather limited. In old Windows systems, no font contains them. In newer Windows systems, from Windows Vista onwards, Cambria Math should be available. It is possible that you have been testing on an old Windows version, but it is also possible that Chrome is unable to find the right font. To give it a helping hand, use a CSS rule that suggests that font, e.g. with the attribute
style="font-family: Cambria Math"
You might consider adding some other fonts to the list, using fonts that are known to contain the characters. See my Guide to using special characters in HTML.
The nasty change is that in HTML 4.01, in the entities section, 〈 and 〉 are defined as referring to U+2329 LEFT-POINTING ANGLE BRACKET “〈” and U+232A RIGHT-POINTING ANGLE BRACKET “〉”. They are logically less satisfactory (and deprecated by the Unicode Standard), but they have somewhat wider font support.
So in addition to declaring fonts that contain the characters you use, you need to decide which pair of these characters you use or whether you use something else; it's a complicated question. If you use them, it is best to use them as such (in a UTF-8 encoded HTML document) or using numeric character references such as ⟨. The reason is that 〈 and 〉 should not be expected to work consistently; they probably work the HTML5 way in all modern browsers, but there is hardly any reason to take the risk, when you can unambiguously indicate the characters you want.
That particular character is simply a unicode codepoint which is an arbitrary number. There are a lot of unicode codepoints that do not have an 'official' symbol. Even if they do have a symbol, it is not necessarily the case that your font has a symbol for that codepoint. If you choose a different font, you may end up with a different symbol.
I looked at the CSS for the page and it shows this character displaying in Arial (plus a bunch of other fonts that do not matter). Windows comes with Arial so it should always pick up that font first. It looks like Arial does not have a symbol for that unicode codepoint. Anytime you do not have a glyph for a codepoint, it puts in some form of a box indicating there is no glyph
It depends on the entity, and the fonts on the system your reader is using. The issue is that these characters are not in the MathJax web fonts, so MathJax has to fall back on system fonts to find them. Some browsers are better at that than others. Your configuration controls what fonts MathJax lists for the browser to look in, so you may want to modify that to include fonts where you know your entities can be found (and you may want to think about the fact that you may have people reading your site on Windows, Mac, and Linux, and also mobile devices, so such decisions are not always easy).
Notice that when you install STIX fonts, it works for you. This is because STIXGeneral is in the default list of fonts that MathJax uses for unknown characters. You want to add others to that list (it is stored in the undefinedFamily property of the HTML-CSS and SVG sections of your configuration). Note however, that IE will stop checking fonts once it encounters a font that is installed on the system, even if it doesn't include the needed character and later fonts in the list do, so you have to be careful about the order that you use.
I have a web app in which a user can change the font family of an input text area in a WSIWYG-kind style. Now, let's say the user inputs some Chinese text in the text area, but selects a Font that has no support for Chinese characters. In my application, I'd like the user to see those nasty squares (or something like that) that are usually shown when the font doesn't support the character. That way, the user would know that the font doesn't support the language and could choose a different one. The issue I'm having is that the browsers (Firefox 17 and Chrome 23) seem to render the Chinese part of the text with fonts (as Arial) that do support those Chinese characters, making the user believe that the font he's trying to use works fine.
Is there a way (I'm guessing through CSS) to prevent this? Is there a way of making the browsers not to be so "nice" for only this time?
Thank you in advance.
As the other answer already explained, the solution is to use a fallback font which includes 'all' unicode codepoints. However the difficult part was to find or built one which doesn't weight a few MBs.
A few years later there is now a more lightweight solution for a fallback font, the NotDef font by Adobe. It shows a box with a cross for 1,111,998 Unicode code points, is only about 22Kb and is using the SIL OPEN FONT LICENSE Version 1.1.
If you don't want to show anything there is also the Adobe Blank font.
You can intercept the font substitution process by throwing in a catchall font, using some equivalent of font-family: userChoice, yourCatchAll where yourCatchAll is a font that has a generic glyph for all characters.
The problem is in finding such a font. The LastResort font distributed by the Unicode Consortium would be ideal, since it also visually indicates the category of the character in broad terms, but its EULA does not seem to allow modifications. It is debatable whether this applies to the construction of web font formats (like .eot and .woff).
The Unicode BMP Fallback Font appears to have more liberal rules of use, but it displays a character simply as its Unicode number in a box (and supports only Basic Multilingual Plane, though it contains all characters that most people ever heard of).
I have a webpage that uses the special character ︾ in the HTML. In Firefox 4.0B12 this looks like a double downward-pointing chevron (︾). In Internet Explorer 8.0.7600.16385, however, this it just looks like ︾.
What do I need to do to get this character to display in IE the way it does in FF?
Thanks,
PaulH
Explicitly specify a font that you know contains that character (eg in a font-family CSS rule), so that you're not relying on the font fallback functionality of the browser (which varies, but Firefox is typically better at it than IE).
U+FE3E is a character intended for use as a close bracket in vertical ideographic text (Chinese, Japanese etc). You shouldn't expect it to be available on a machine that doesn't have East Asian fonts installed, and using it to get a particular shape unrelated to parentheses is really a misuse. I would not use it on the web. There are a limited number of ‘symbol’ characters that generally render reliably across the main OS default installs and this isn't one of them.
Make sure to end the character reference with a semicolon, like ︾.
You need to include the semi-colon after the HTML code: ︾.