A string can be quoted with single or double quotes:

var a = "Hello world";
var b = 'Hello world';

Additionally, strings can be triple-quoted, which means they are delimited by three (matching) quote characters:

var c = """Hello world""";
var d = '''Hello world''';

A triple quoted string may span multiple lines, and can contain single and double quotes with no need for escaping:

var c = """
  Triple-quoted strings can 
  include both "double" and 'single'
  quotes without escaping.
""";