String.prototype.replace()

The replace() method returns a new string with some or all matches of a pattern replaced by a replacement. 
The pattern can be a string or a RegExp, and the replacement can be a string or a function to be called for each match.
语法：
　　str.replace(regexp|substr, newSubStr|function[, flags])

Parameters

regexp (pattern)

A RegExp object or literal. The match is replaced by the return value of parameter #2.

substr (pattern)

A String that is to be replaced by newSubStr. It is treated as a verbatim string and is notinterpreted as a regular expression.

newSubStr (replacement)

The String that replaces the substring received from parameter #1. A number of special replacement patterns are supported; see the "Specifying a string as a parameter" section below.

function (replacement)

A function to be invoked to create the new substring (to put in place of the substring received from parameter #1). The arguments supplied to this function are described in the "Specifying a function as a parameter" section below.

例子：

例1：

var str = 'Twas the night before Xmas...';

var newstr = str.replace(/xmas/i, 'Christmas');

console.log(newstr);  // Twas the night before Christmas...

例2：

var re = /apples/gi;

var str = 'Apples are round, and apples are juicy.';

var newstr = str.replace(re, 'oranges');

console.log(newstr);  // oranges are round, and oranges are juicy.

例3：

var re = /(\w+)\s(\w+)/;

var str = 'John Smith';

var newstr = str.replace(re, '$2, $1');

console.log(newstr);  // Smith, Joh

例4：

function styleHyphenFormat(propertyName) {

  function upperToHyphenLower(match) {

    return '-' + match.toLowerCase();

  }

  return propertyName.replace(/[A-Z]/g, upperToHyphenLower);

}

例5：

function replacer(match, p1, p2, p3, offset, string) {

  // p1 is nondigits, p2 digits, and p3 non-alphanumerics

  console.log(arguments);

  return [p1, p2, p3].join(' - ');

}

var newString = 'abc12345#$*%aaa'.replace(/([^\d]*)(\d*)([^\w]*)/, replacer);