Many languages support multiline strings through a heredoc type syntax.
Python:
longStr = """This
is
a
multiline
string"""
C#:
string longStr = @"This
is
a
multiline
string";
PHP:
$foo = <<EOF
This
is
a
multiline
string
EOF
ECMAScript supports multiline strings, but the continuation character can be cumbersome
var longString = "This\
is\
a\
multiline\
string";
If you forget the continuation character, it can cause confusion trying to determine where the issue is.
Closing as fixed, since http://wiki.ecmascript.org/doku.php?id=harmony:quasis takes care of this need.