When lines of text wrap, the type of script affects the expected behavior - particularly with regard to the treatment of white space around line breaks in the code.

Chinese and Japanese scripts do not delimit words with spaces, and wrap on a character-by-character basis. There are, however, some rules (called kinsoku rules in Japan) that forbid certain characters (mostly final punctuation) from appearing at the beginning of a line, and others that forbid certain characters appearing at the end of a line.

Thai script uses spaces to delimit phrases, rather than words, and typically does not use sentence final punctuation. There is, however, a strong concept of a word, and text should be wrapped at word boundaries. Some Thai systems rely on users adding zero-width spaces to indicate where wrapping is appropriate, but it is more common to use a dictionary to determine word boundaries.

Unless the style sheet requires that space be preserved, when dealing with the Latin script, the general process of displaying text that is wrapped onto a new line in the source involves first reducing all white space at the beginning and end of the line to a single space. Then, unless the style sheet says otherwise, the line break characters and any surrounding spaces are boiled down to a single space.

The line breaking properties in CSS3 will allow you to indicate appropriate behavior for scripts like Chinese, Japanese and Thai, where adding a space between wrapped text may not be appropriate. (This is quite a complicated area, and discussion is still going on about how best to handle this.)

Some of the CSS3 properties will allow you to specify whether or not to wrap differently in the middle of embedded text from another script. For example, if you have Latin text in the middle of Chinese, should it wrap character by character or word by word? Both are valid, and CSS should allow you to choose according to your general preferences or the context. (See the two examples on the slide.)