javascript에서 문자열 추출함수를 찾다가 좋은걸 찾았다.
그림설명까지 ~ 추출방법은 substring( 시작, 끝)
아주 간단하다.
이것도 문자열 추출함수 substr이다
http://freewebdesigntutorials.com/javaScriptTutorials/jsStringObject/substrMethod.htm
그리고 역시나 래퍼런스를 참조하면 더 많이 알수있다.
http://www.w3schools.com/jsref/jsref_obj_string.asp
JavaScript String Object Reference
String Object Methods
FF: Firefox, N: Netscape, IE: Internet Explorer
| Method | Description | FF | N | IE |
|---|---|---|---|---|
| anchor() | Creates an HTML anchor | 1 | 2 | 3 |
| big() | Displays a string in a big font | 1 | 2 | 3 |
| blink() | Displays a blinking string | 1 | 2 | |
| bold() | Displays a string in bold | 1 | 2 | 3 |
| charAt() | Returns the character at a specified position | 1 | 2 | 3 |
| charCodeAt() | Returns the Unicode of the character at a specified position | 1 | 4 | 4 |
| concat() | Joins two or more strings | 1 | 4 | 4 |
| fixed() | Displays a string as teletype text | 1 | 2 | 3 |
| fontcolor() | Displays a string in a specified color | 1 | 2 | 3 |
| fontsize() | Displays a string in a specified size | 1 | 2 | 3 |
| fromCharCode() | Takes the specified Unicode values and returns a string | 1 | 4 | 4 |
| indexOf() | Returns the position of the first occurrence of a specified string value in a string | 1 | 2 | 3 |
| italics() | Displays a string in italic | 1 | 2 | 3 |
| lastIndexOf() | Returns the position of the last occurrence of a specified string value, searching backwards from the specified position in a string | 1 | 2 | 3 |
| link() | Displays a string as a hyperlink | 1 | 2 | 3 |
| match() | Searches for a specified value in a string | 1 | 4 | 4 |
| replace() | Replaces some characters with some other characters in a string | 1 | 4 | 4 |
| search() | Searches a string for a specified value | 1 | 4 | 4 |
| slice() | Extracts a part of a string and returns the extracted part in a new string | 1 | 4 | 4 |
| small() | Displays a string in a small font | 1 | 2 | 3 |
| split() | Splits a string into an array of strings | 1 | 4 | 4 |
| strike() | Displays a string with a strikethrough | 1 | 2 | 3 |
| sub() | Displays a string as subscript | 1 | 2 | 3 |
| substr() | Extracts a specified number of characters in a string, from a start index | 1 | 4 | 4 |
| substring() | Extracts the characters in a string between two specified indices | 1 | 2 | 3 |
| sup() | Displays a string as superscript | 1 | 2 | 3 |
| toLowerCase() | Displays a string in lowercase letters | 1 | 2 | 3 |
| toUpperCase() | Displays a string in uppercase letters | 1 | 2 | 3 |
| toSource() | Represents the source code of an object | 1 | 4 | - |
| valueOf() | Returns the primitive value of a String object | 1 | 2 | 4 |
String Object Properties
| Property | Description | FF | N | IE |
|---|---|---|---|---|
| constructor | A reference to the function that created the object | 1 | 4 | 4 |
| length | Returns the number of characters in a string | 1 | 2 | 3 |
| prototype | Allows you to add properties and methods to the object | 1 | 2 | 4 |
This tutorial introduces the substring() method, from the JavaScript String object. The substring() method is designed to extract a substring of text from another string, while not modifying the original string. The substring() method takes at least one argument (to take a substring ending with the end of the original string), and an optional second argument indicating the position index at which the extracted substring should stop.
Related string method:
The substr() method extracts a substring from a fixed start index and relative string length.
Using the substring() Method with One Argument
In the script below, we will extract a substring using only one argument:
var carter = "I learn JavaScript.";
alert( carter.substring(8) );
By only passing one argument (the start position index), the substring() method extracts characters until it reaches the end of the string on which it is applied: 
In this respect, the substring() method behaves exactly like the substr() method, when only the start position index is passed.
Using the substring() Method with Two Arguments
The substring() method accepts a second optional argument: it indicates the point at which it should stop extracting characters (in other words, the second argument indicates the end position index).
var carter = "I learn JavaScript.";
alert( carter.substring(8,12) ); JavaScript's charAt(), substr(), and substring() Methods
The JavaScript string objects includes three methods that allow you to extract substrings of text: the charAt() method (for a single character), the substr() method (fixed start index and relative length), and the substring() method (for a fixed start and end index positions).
The script below how to obtain the same result from each of the three methods:
var carter = "I learn JavaScript.";
// Let's extract the "J" in "JavaScript"
var outCode;
outCode = carter.charAt(8) +"\n";
outCode += carter.substr(8,1) +"\n";
outCode += carter.substring(8,9);
alert( outCode );
After storing the results, separated by a new line character, the last line of code produces the following result: 
Test the substring() Method
Interactively test the substring() method by editing the JavaScript code below and clicking the Test substring() Method button.
