?
//parse_url /^(?:([A-Za-z]+):)?(\/{0,3})([0-9.\-A-Za-z]+)(?::(\d+))?(?:\/([^?#]*))?(?:\?([^#]*))?(?:#(.*))?$/ //ignore case, the other two flags are 'g', 'm' /^abc$/i "into".match(/in|int/) \d is same as [0-9], \D is same as [^0-9] \s is same as[\f\n\r\t...], \S is same as[^...] \w is same as [0-9A-Z_a-z] // \1 is a reference to group 1, \2 to group2 /([A-Za-z]+)\s+\1/ //regexp class [aeiou] //quantifier /w{3}/ /w{3,6}/ /w{3,}/ var m = "wwwwdddd".match(/(w{3,})(d+)/); m should be an array ["wwwwdddd", "wwww", "dddd"]