Question

As we know, jQuery uses $ as an alias for the jQuery.
Are there others signs available that i can use for my own Javascript-Framework?

Answer 1

Remember that an “alias” is just another variable. Aside from the underscore and dollar characters, from the ECMAScript 5 spec:

Unicode escape sequences are also permitted in an IdentifierName,
where they contribute a single character to the IdentifierName, as
computed by the CV of the UnicodeEscapeSequence (see 7.8.4). The \
preceding the UnicodeEscapeSequence does not contribute a character to
the IdentifierName. A UnicodeEscapeSequence cannot be used to put a
character into an IdentifierName that would otherwise be illegal. In
other words, if a \ UnicodeEscapeSequence sequence were replaced by
its UnicodeEscapeSequence’s CV, the result must still be a valid
IdentifierName that has the exact same sequence of characters as the
original IdentifierName. All interpretations of identifiers within
this specification are based upon their actual characters regardless
of whether or not an escape sequence was used to contribute any
particular characters.

To put it simply, valid JavaScript variable identifiers have to start with a letter, dollar symbol or underscore symbol, and can contain unicode character escape sequences. The relevant part of the grammar from the spec:

IdentifierStart ::
    UnicodeLetter
    $
    _ 
    \ UnicodeEscapeSequence

In the case of writing a library, if you want to use $ there shouldn’t be a problem – jQuery provides it’s noConflict method to handle that exact situation.