javascript regex
// \d Any digit character
// \w An alphanumeric character (“word character”)
// \s Any whitespace character (space, tab, newline, and similar)
// \D A character that is not a digit
// \W A nonalphanumeric character
// \S A nonwhitespace character
// . Any character except for newline
// /abc/ A sequence of characters
// /[abc]/ Any character from a set of characters
// /[^abc]/ Any character not in a set of characters
// /[0-9]/ Any character in a range of characters
// /x+/ One or more occurrences of the pat