/** * @class RegExp * * Creates a regular expression object for matching text according to a pattern. * * When using the constructor function, the normal string escape rules (preceding * special characters with \ when included in a string) are necessary. For * example, the following are equivalent: * * var re = new RegExp("\\w+"); * var re = /\w+/; * * Notice that the parameters to the literal format do not use quotation marks to * indicate strings, while the parameters to the constructor function do use * quotation marks. So the following expressions create the same regular * expression: * * /ab+c/i; * new RegExp("ab+c", "i"); * * # Special characters in regular expressions * * | Character | Meaning * |:-----------------|:-------------------------------------------------------------------------------------- * | `\` | For characters that are usually treated literally, indicates that the next character * | | is special and not to be interpreted literally. * | | For example, `/b/` matches the character 'b'. By placing a backslash in front of b, that * | | is by using `/\b/`, the character becomes special to mean match a word boundary. * | | * | | _or_ * | | * | | For characters that are usually treated specially, indicates that the next character is * | | not special and should be interpreted literally. * | | * | | For example, `*` is a special character that means 0 or more occurrences of the preceding * | | character should be matched; for example, `/a*\/` means match 0 or more "a"s. To match * * | | literally, precede it with a backslash; for example, `/a\*\/` matches 'a*'. * | | * | `^` | Matches beginning of input. If the multiline flag is set to true, also matches * | | immediately after a line break character. * | | * | | For example, `/^A/` does not match the 'A' in "an A", but does match the first 'A' in * | | "An A". * | | * | `$` | Matches end of input. If the multiline flag is set to true, also matches immediately * | | before a line break character. * | | * | | For example, `/t$/` does not match the 't' in "eater", but does match it in "eat". * | | * | `*` | Matches the preceding item 0 or more times. * | | * | | For example, `/bo*\/` matches 'boooo' in "A ghost booooed" and 'b' in "A bird warbled", * | | but nothing in "A goat grunted". * | | * | `+` | Matches the preceding item 1 or more times. Equivalent to `{1,}`. * | | * | | For example, `/a+/` matches the 'a' in "candy" and all the a's in "caaaaaaandy". * | | * | `?` | Matches the preceding item 0 or 1 time. * | | * | | For example, `/e?le?/` matches the 'el' in "angel" and the 'le' in "angle." * | | * | | If used immediately after any of the quantifiers `*`, `+`, `?`, or `{}`, makes the quantifier * | | non-greedy (matching the minimum number of times), as opposed to the default, which is * | | greedy (matching the maximum number of times). * | | * | | Also used in lookahead assertions, described under `(?=)`, `(?!)`, and `(?:)` in this table. * | | * | `.` | (The decimal point) matches any single character except the newline characters: \n \r * | | \u2028 or \u2029. (`[\s\S]` can be used to match any character including new lines.) * | | * | | For example, `/.n/` matches 'an' and 'on' in "nay, an apple is on the tree", but not 'nay'. * | | * | `(x)` | Matches `x` and remembers the match. These are called capturing parentheses. * | | * | | For example, `/(foo)/` matches and remembers 'foo' in "foo bar." The matched substring can * | | be recalled from the resulting array's elements `[1], ..., [n]` or from the predefined RegExp * | | object's properties `$1, ..., $9`. * | | * | `(?:x)` | Matches `x` but does not remember the match. These are called non-capturing parentheses. * | | The matched substring can not be recalled from the resulting array's elements `[1], ..., [n]` * | | or from the predefined RegExp object's properties `$1, ..., $9`. * | | * | `x(?=y)` | Matches `x` only if `x` is followed by `y`. For example, `/Jack(?=Sprat)/` matches 'Jack' only if * | | it is followed by 'Sprat'. `/Jack(?=Sprat|Frost)/` matches 'Jack' only if it is followed by * | | 'Sprat' or 'Frost'. However, neither 'Sprat' nor 'Frost' is part of the match results. * | | * | `x(?!y)` | Matches `x` only if `x` is not followed by `y`. For example, `/\d+(?!\.)/` matches a number only * | | if it is not followed by a decimal point. * | | * | | `/\d+(?!\.)/.exec("3.141")` matches 141 but not 3.141. * | | * | `x|y` | Matches either `x` or `y`. * | | * | | For example, `/green|red/` matches 'green' in "green apple" and 'red' in "red apple." * | | * | `{n}` | Where `n` is a positive integer. Matches exactly n occurrences of the preceding item. * | | * | | For example, `/a{2}/` doesn't match the 'a' in "candy," but it matches all of the a's * | | in "caandy," and the first two a's in "caaandy." * | | * | `{n,}` | Where `n` is a positive integer. Matches at least n occurrences of the preceding item. * | | * | | For example, `/a{2,}/` doesn't match the 'a' in "candy", but matches all of the a's in * | | "caandy" and in "caaaaaaandy." * | | * | `{n,m}` | Where `n` and `m` are positive integers. Matches at least `n` and at most `m` occurrences of the * | | preceding item. * | | * | | For example, `/a{1,3}/` matches nothing in "cndy", the 'a' in "candy," the first two a's * | | in "caandy," and the first three a's in "caaaaaaandy". Notice that when matching * | | "caaaaaaandy", the match is "aaa", even though the original string had more a's in it. * | | * | `[xyz]` | A character set. Matches any one of the enclosed characters. You can specify a range of * | | characters by using a hyphen. * | | * | | For example, `[abcd]` is the same as `[a-d]`. They match the 'b' in "brisket" and the 'c' * | | in "chop". * | | * | `[^xyz]` | A negated or complemented character set. That is, it matches anything that is not * | | enclosed in the brackets. You can specify a range of characters by using a hyphen. * | | * | | For example, `[^abc]` is the same as `[^a-c]`. They initially match 'r' in "brisket" and * | | 'h' in "chop." * | | * | `[\b]` | Matches a backspace. (Not to be confused with `\b`.) * | | * | `\b` | Matches a word boundary, such as a space. (Not to be confused with `[\b]`.) * | | * | | For example, `/\bn\w/` matches the 'no' in "noonday"; `/\wy\b/` matches the 'ly' in * | | "possibly yesterday." * | | * | `\B` | Matches a non-word boundary. * | | * | | For example, `/\w\Bn/` matches 'on' in "noonday", and `/y\B\w/` matches 'ye' in "possibly * | | yesterday." * | | * | `\cX` | Where X is a letter from A - Z. Matches a control character in a string. * | | * | | For example, `/\cM/` matches control-M in a string. * | | * | `\d` | Matches a digit character in the basic Latin alphabet. Equivalent to `[0-9]`. * | | * | | For example, `/\d/` or `/[0-9]/` matches '2' in "B2 is the suite number." * | | * | `\D` | Matches any non-digit character in the basic Latin alphabet. Equivalent to `[^0-9]`. * | | * | | For example, `/\D/` or `/[^0-9]/` matches 'B' in "B2 is the suite number. * | | * | `\f` | Matches a form-feed. * | | * | `\n` | Matches a linefeed. * | | * | `\r` | Matches a carriage return. * | | * | `\s` | Matches a single white space character, including space, tab, form feed, line feed and * | | other unicode spaces. Equivalent to: * | | * | | `[\t\n\v\f\r \u00a0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000]` * | | * | | For example, `/\s\w*\/` matches ' bar' in "foo bar." * | | * | `\S` | Matches a single character other than white space. Equivalent to: * | | * | | `[^\t\n\v\f\r \u00a0\u2000\u2001\u2002\u2003\u2004\u2005\u2006\u2007\u2008\u2009\u200a\u200b\u2028\u2029\u3000]` * | | * | | For example, `/\S\w*\/` matches 'foo' in "foo bar." * | | * | `\t` | Matches a tab. * | | * | `\v` | Matches a vertical tab. * | | * | `\w` | Matches any alphanumeric character from the basic Latin alphabet, including the * | | underscore. Equivalent to `[A-Za-z0-9_]`. * | | * | | For example, `/\w/` matches 'a' in "apple," '5' in "$5.28," and '3' in "3D." * | | * | `\W` | Matches any character that is not a word character from the basic Latin alphabet. Equivalent * | | to `[^A-Za-z0-9_]`. * | | * | | For example, `/\W/` or `/[^A-Za-z0-9_]/` matches '%' in "50%." * | | * | `\n` | Where `n` is a positive integer. A back reference to the last substring matching the n * | | parenthetical in the regular expression (counting left parentheses). * | | * | | For example, `/apple(,)\sorange\1/` matches 'apple, orange,' in "apple, orange, cherry, * | | peach." A more complete example follows this table. * | | * | `\0` | Matches a NULL character. Do not follow this with another digit. * | | * | `\xhh` | Matches the character with the code `hh` (two hexadecimal digits) * | | * | `\uhhhh` | Matches the character with the Unicode value `hhhh` (four hexadecimal digits) * * The literal notation provides compilation of the regular expression when the expression is evaluated. Use * literal notation when the regular expression will remain constant. For example, if you use literal notation * to construct a regular expression used in a loop, the regular expression won't be recompiled on each iteration. * * The constructor of the regular expression object, for example, new RegExp("ab+c"), provides runtime * compilation of the regular expression. Use the constructor function when you know the regular expression * pattern will be changing, or you don't know the pattern and are getting it from another source, such as user input. * *
* Documentation for this class comes from MDN * and is available under Creative Commons: Attribution-Sharealike license. *
*/ /** * @method constructor * Creates new regular expression object. * * @param {String} pattern * The text of the regular expression. * @param {String} flags * If specified, flags can have any combination of the following values: * * - "g" - global match * - "i" - ignore case * - "m" - Treat beginning and end characters (^ and $) as working over multiple lines * (i.e., match the beginning or end of _each_ line (delimited by \n or \r), not * only the very beginning or end of the whole input string) */ //Methods /** * @method exec * Executes a search for a match in its string parameter. * * If the match succeeds, the `exec` method returns an array and updates properties of the regular * expression object. The returned array has the matched text as the first item, and then one item for * each capturing parenthesis that matched containing the text that was captured. If the match fails, * the `exec` method returns `null`. * * If you are executing a match simply to find true or false, use the `test` method or the `String * search` method. * * Consider the following example: * * // Match one d followed by one or more b's followed by one d * // Remember matched b's and the following d * // Ignore case * var re = /d(b+)(d)/ig; * var result = re.exec("cdbBdbsbz"); * * The following table shows the results for this script: * * | Object | Property/Index | Description | Example * |:-----------------|:---------------|:---------------------------------------------------------------------|:--------------------- * | `result` | | The content of myArray. | `["dbBd", "bB", "d"]` * | | `index` | The 0-based index of the match in the string | `1` * | | `input` | The original string. | `cdbDdbsbz` * | | `[0]` | The last matched characters. | `dbBd` * | | `[1], ...[n]` | The parenthesized substring matches, if any. The number of possible | `[1] = bB` * | | | parenthesized substrings is unlimited. | `[2] = d` * | `re` | `lastIndex` | The index at which to start the next match. | `5` * | | `ignoreCase` | Indicates the "`i`" flag was used to ignore case. | `true` * | | `global` | Indicates the "`g`" flag was used for a global match. | `true` * | | `multiline` | Indicates the "`m`" flag was used to search in strings across | `false` * | | | multiple lines. | * | | `source` | The text of the pattern. | d(b+)(d) * * If your regular expression uses the "`g`" flag, you can use the `exec` method multiple times to find * successive matches in the same string. When you do so, the search starts at the substring of `str` * specified by the regular expression's `lastIndex` property (`test` will also advance the `lastIndex` * property). For example, assume you have this script: * * var myRe = /ab*\/g; * var str = "abbcdefabh"; * var myArray; * while ((myArray = myRe.exec(str)) != null) * { * var msg = "Found " + myArray[0] + ". "; * msg += "Next match starts at " + myRe.lastIndex; * print(msg); * } * * This script displays the following text: * * Found abb. Next match starts at 3 * Found ab. Next match starts at 9 * * You can also use `exec()` without creating a RegExp object: * * var matches = /(hello \S+)/.exec('This is a hello world!'); * alert(matches[1]); * * This will display an alert containing 'hello world!'; * * @param {String} str The string against which to match the regular expression. * @return {Array} Array of results or `NULL`. */ /** * @method test * Tests for a match in its string parameter. * * When you want to know whether a pattern is found in a string use the test method (similar to the * `String.search` method); for more information (but slower execution) use the exec method (similar to * the `String.match` method). As with exec (or in combination with it), test called multiple times on * the same global regular expression instance will advance past the previous match. * * The following example prints a message which depends on the success of the test: * * function testinput(re, str){ * if (re.test(str)) * midstring = " contains "; * else * midstring = " does not contain "; * document.write (str + midstring + re.source); * } * * @param {String} str The string against which to match the regular expression. * @return {Boolean} true if string contains any matches, otherwise returns false. */ /** * @method toString * Returns a string representing the specified object. Overrides the `Object.prototype.toString` * method. * * The RegExp object overrides the `toString` method of the `Object` object; it does not inherit * `Object.toString`. For RegExp objects, the `toString` method returns a string representation of the * regular expression. * * The following example displays the string value of a RegExp object: * * myExp = new RegExp("a+b+c"); * alert(myExp.toString()); // displays "/a+b+c/" * * @return {String} Regular expression as a string. */ //Properties // Note that several of the RegExp properties have both long and short (Perl-like) names. // Both names always refer to the same value. Perl is the programming language from which // JavaScript modeled its regular expressions. /** * @property {Boolean} global * Whether to test the regular expression against all possible matches in a * string, or only against the first. * * `global` is a property of an individual regular expression object. * * The value of `global` is true if the "`g`" flag was used; otherwise, `false`. The "`g`" flag * indicates that the regular expression should be tested against all possible matches in a string. * * You cannot change this property directly. */ /** * @property {Boolean} ignoreCase * Whether to ignore case while attempting a match in a string. * * `ignoreCase` is a property of an individual regular expression object. * * The value of `ignoreCase` is true if the "`i`" flag was used; otherwise, false. The "`i`" flag indicates * that case should be ignored while attempting a match in a string. * * You cannot change this property directly. */ /** * @property {Number} lastIndex * The index at which to start the next match. A read/write integer property that specifies the index * at which to start the next match. * * `lastIndex` is a property of an individual regular expression object. * * This property is set only if the regular expression used the "`g`" flag to indicate a global search. * The following rules apply: * * - If `lastIndex` is greater than the length of the string, `regexp.test` and `regexp.exec` fail, * and `lastIndex` is set to 0. * - If `lastIndex` is equal to the length of the string and if the regular expression matches the * empty string, then the regular expression matches input starting at `lastIndex`. * - If `lastIndex` is equal to the length of the string and if the regular expression does not match * the empty string, then the regular expression mismatches input, and `lastIndex` is reset to 0. * - Otherwise, `lastIndex` is set to the next position following the most recent match. * * For example, consider the following sequence of statements: * * - `re = /(hi)?/g` Matches the empty string. * - `re("hi")` Returns `["hi", "hi"]` with `lastIndex` equal to 2. * - `re("hi")` Returns `[""]`, an empty array whose zeroth element is the match string. In this * case, the empty string because `lastIndex` was 2 (and still is 2) and "`hi`" has length 2. */ /** * @property {Boolean} multiline * Whether or not to search in strings across multiple lines. * * `multiline` is a property of an individual regular expression object.. * * The value of `multiline` is true if the "`m`" flag was used; otherwise, `false`. The "`m`" flag * indicates that a multiline input string should be treated as multiple lines. For example, if "`m`" * is used, "`^`" and "`$`" change from matching at only the start or end of the entire string to the * start or end of any line within the string. * * You cannot change this property directly. */ /** * @property {String} source * The text of the pattern. * * A read-only property that contains the text of the pattern, excluding the forward slashes. * * `source` is a property of an individual regular expression object. * * You cannot change this property directly. */