string-no-newline
Disallow (unescaped) newlines in strings.
a {
  content: "first
    second";     ↑
}                ↑
/**              ↑
 * The newline here */The spec says this: “A string cannot directly contain a newline. To include a newline in a string, use an escape representing the line feed character in ISO-10646 (U+000A), such as ‘’ or ‘\00000a’.” And also: “It is possible to break strings over several lines, for aesthetic or other reasons, but in such a case the newline itself has to be escaped with a backslash (\).”
Options
true
The following patterns are considered violations:
a {
  content: "first
    second";
}[title="something
is probably wrong"] {}a {
  font-family: "Times
    New
    Roman";
}The following patterns are not considered violations:
a {
  content: "first\Asecond";
}a {
  content: "first\\nsecond";
}[title="nothing\
  is wrong"] {}a {
  font-family: "Times New Roman";
}