JavaScript replace () replaces all usages

Source: Internet
Author: User
Tags function prototype regular expression

String.Replace () Introduction


String.Replace (RegExp, replacement)

RegExp: The regular expression for which you want to perform the substitution operation. If a string is passed in, it is treated as a normal character, and only one substitution operation is performed, and if the regular expression is present with the global (g) modifier, all occurrences of the target character are replaced. Only one substitution operation will be performed.

Replacement: The character you want to replace.

The simplest example

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<script type= "Text/javascript" >

var str= "Visit microsoft!";
document.write (Str.replace ("Microsoft", "W3Schools"));


The return value is the string after the substitution operation.

Simple usage of string.replace ()

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<script type= "Text/javascript" >

var str= "Visit microsoft!";
document.write (Str.replace (/microsoft/i, "W3Schools"));


String.Replace () Replaces all occurrences of the target character

var text= "JavaScript is very powerful! JAVASCRIPT is one of my favorite languages! ";

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Text.replace (/javascript/ig, "JavaScript"); Return:

JavaScript is very powerful! JavaScript is one of my favorite languages!

String.Replace () to implement the swap position

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var name= "Doe, John";
Name.replace (/(w+) s*,s* (w+)/, "$ $"); Back: John Doe

String.Replace () implementation replaces all double quotes with characters enclosed in brackets

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The var text = ' JavaScript ' is very powerful! ';

Text.replace ([^ "]*)"/g, "[$]"); Back: [JavaScript] very powerful!

String.Replace () capitalize all characters first letter

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var text = ' A journey of a thousand miles begins with single step. '

Text.replace (/bw+b/g, function (word) {

Return word.substring (0,1). toUpperCase () + word.substring (1);


Return: A Journey of a thousand Miles begins with single step.

The replace () method in JavaScript replaces the first matching character directly with str.replace ("Apples", "oranges").

Replaces all matching characters with/g,/I ignores case

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str = "Apples are round, and Apples are juicy.";
Newstr=str.replace (/apples/gi, "oranges");
document.write (NEWSTR)
</SCRIPT> This prints "oranges are round, and oranges are juicy."

JavaScript's string-Class built-in function replace (regexp, newstring) function provides a string substitution function, which can be seen from the function prototype to support Regular EXP. This function is very useful, but there are a few places where there is a bit of confusion, the following is illustrated by the actual example:
For example, we now want to target the string

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var src= "<a href=" "target=" _blank ">xxx</a>"

To replace the HTML double quotes in which the transfer character is "real", normal we will call Src.replace (/"/g, '") directly; to achieve the goal, but JS easy to confuse is that this does not actually change the value of SRC, The actual test found that the return value is the result we need, and SRC itself does not change, so in practice we need to do the following to complete our functions:

  code is as follows copy code
src= Src.replace (/"/g, '");
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