es in Java

Encoder Code 128 Code Set C in Java es

would look like this:

Encoding characters is quite important if you want to validate your markup For example, consider when you have nontrivial query strings in (X)HTML links like so:

For this line to validate, you must encode the special characters in the link like so:

Do not, however, take this as advice to change ampersands in typed URLs everywhere you encounter them, such as within e-mails or the browser s location bar Typically, a browser will exchange an entity for its correct value, but this change may not take place in other environments Commonly, you will also have trouble when using characters that are part of (X)HTML itself, particularly the less than (<) and greater than (>) symbols and, of course, the ampersand that starts entities As an example, consider this contrived example with a mathematical expression:

Appendix A:

For the greatest safety, the markup should have had the special characters encoded like so:

We note that this example is fairly contrived and often just an extra space will allow the validator (and browser) to tokenize the text correctly For example,

will likely validate The loose enforcement of special character handling is both a blessing and a curse It leads to sloppy usage and surprising bugs Sloppy syntax is troubling because interpretation may vary browser to browser Consider the point of case sensitivity of named entities in browsers Named entities are supposed to be case sensitive For example, à and À are two different characters

But does that hold for all characters Apparently not some entities like © are generally case insensitive, while others like ™ may vary by browser, and others like ¥ will always be case sensitive

Initial drafts of HTML5 attempted to formalize what named entities should be case insensitive; these drafts focused on the commonly used and supported entities The current list of what should be case-insensitive named entities is shown in Table A-1 Best practice, however, would be not to rely on case insensitivity of named entities, it is still inconsistent In general, lax syntax enforcement and permissive interpretation of entities in browsers just leads to all sorts of small quirks Consider

Part III:

Named Entity & © > < " ® ™ TABLE A-1

HTML5 Alias & © > < " ® ™

Numbered Entity & © > < " ® ™

Unicode Entity & © > < " ® ™

Description Ampersand Copyright Greater than Less than Double quotes Registration mark Trademark symbol

Under Internet Explorer, the rendering engine even in a strict mode will fix this problem and effectively convert this into

While it turns out that SGML (and thus traditional HTML) does allow the final semicolon to be left off in an entity in some cases, the preceding example clearly indicates it does not allow for that latitude in the middle of words Just as when dealing with markup and CSS, it is best to get syntax right rather than rely on some variable fix-up applied by a browser s rendering engine There will be instances when you may get the syntax correct but the browser may not be able to render the characters meaningfully The reasons for nonsupport can vary and may be because a particular font is missing or the operating environment or browser is unable to render the character Generally, browsers will present these failures as boxes or diamonds, like so:

Appendix A:

Table A-2 lists the standard entities found in even the oldest versions of HTML and their intended renderings This is the base set of characters supported by ASCII character sets, and future extensions for full ISO-8859-1 follow In traditional HTML pages, authors may use this encoding, which may be specified in the HTTP header:

Content-Type: text/html; charset=ISO-8859-1

Or more commonly, it will appear in a <meta> tag like so: