JavaScript Replace () method

From: http://www.w3school.com.cn/jsref/jsref_replace.asp

Definition and usage

The replace () method is used to replace other characters with some characters in a string, or to replace a substring that matches a regular expression.

Grammar

Stringobject.replace (regexp/substr,replacement)

Parameters	Description
Regexp/substr	Necessary. A RegExp object that specifies the substring or pattern to replace. Note that if the value is a string, it is used as the direct volume text pattern to be retrieved, instead of being converted to the RegExp object first.
Replacement	Necessary. A string value. A function that specifies replacement text or generates alternate text.

return value

A new string that is obtained after the first match or all matches of regexp have been replaced with replacement .

Description

The replace () method of the string Stringobject performs a find-and-replace operation. It looks for substrings in Stringobject that match regexp, and then replaces them with replacement . If RegExp has global flag G, then the Replace () method replaces all matching substrings. Otherwise, it replaces only the first matched substring.

replacement can be a string, or it can be a function. If it is a string, then each match is replaced by a string. However, the $ character in replacement has a specific meaning. As shown in the following table, it shows that the resulting string from a pattern match will be used for substitution.

character	Replace text
$, $ 、...、	The text that matches the 1th to 99th sub-expression in RegExp.
$&	A substring that matches the regexp.
$`	The text that is located to the left of the matching substring.
$	The text on the right side of the matching substring.
$$	Direct volume symbol.

Note: ECMAScript v3 stipulates that the parameter replacement of the replace () method can be a function instead of a string. In this case, each match calls the function, and the string it returns is used as the replacement text. The first parameter of the function is a string that matches the pattern. The next parameter is a string that matches the subexpression in the pattern and can have 0 or more of these parameters. The next argument is an integer that declares where the match appears in the Stringobject. The last parameter is the stringobject itself.

Example 1

In this example, we will replace "Microsoft" in the string with "W3school":

<script type= "Text/javascript" >var str= "Visit microsoft!" document.write ( str.replace(/Microsoft/, "W3School") ) </script>

Output:

Visit w3school!

Example 2

In this example, we will perform a global substitution, and whenever "Microsoft" is found, it is replaced with "W3school":

<script type= "Text/javascript" >var str= "Welcome to microsoft! "Str=str +" We are proud to announce that Microsoft have "Str=str +" one of the largest WEB developers sites in the world. " document.write ( str.replace(/Microsoft/g, "W3School") ) </script>

Output:

Welcome to w3school! We is proud to announce this W3schoolhas one of the largest WEB developers sites in the world.

Example 3

You can use the code provided in this example to ensure that the matching string is correct for uppercase characters:

Text = "JavaScript Tutorial"; Text.replace (/javascript/i, "JavaScript");

Example 4

In this example, we will convert "Doe, John" to the form of "John Doe":

Name = "Doe, John"; Name.replace (/(\w+) \s*, \s* (\w+)/, "$ $");

Example 5

In this example, we'll replace all the curly quotes with straight quotes:

name = ' A ', "B" '; Name.replace (/"([^"]*) "/g," ' $ ' ");

Example 6

In this example, we will convert all of the words in the string to uppercase in the first letter:

Name = ' aaa bbb ' CCC '; Uw=name.replace (/\b\w+\b/g, function (word) {  return word.substring (0,1). toUpperCase () + Word.substring (1);}  );

Tiy

Replace () 1

How to replace characters in a string with replace ().

Replace () 2-Global Search

How to use Replace () for global substitution.

Replace () 3-case insensitive search

How to use replace () to ensure that uppercase letters are correct.

Replace () 4

How to use Replace () to convert the name format.

Replace () 5

How to use Replace () to convert quotation marks.

Replace () 6

How to use replace () to convert the first letter of a word to uppercase.

JavaScript replace () method