Table of Contents

string.substr(startIndex, length)

Arguments

startIndex

The integer position of the first character to extract from string. If startIndex is negative, the position is measured from the end of the string, where -1 is the last character, -2 is the second-to-last character, and so on (i.e., a negative startIndex specifies the character at string.length + startIndex).

length

The number of characters to extract from string, starting at (and including) the startIndex. If not specified, all the characters from startIndex to the end of string are extracted.

Returns

A substring of string, starting at startIndex and including length characters. If length is omitted, the result contains characters from startIndex to the end of string.

Description

The substr( ) method is one of three methods that can be used to extract a substring from a string (the others being slice( ) and substring( )). The substr( ) method extracts a string based on the number of characters specified by length, not based on an ending character index.

Usage

Note that substr( ) does not modify string; it returns a completely new string.

Example

var fullName = "Steven Sid Mumby";
   
middleName = fullName.substr(7, 3);       // Assigns "Sid" to middleName
firstName  = fullName.substr(0, 6);       // Assigns "Steven" to firstName
lastName   = fullName.substr(11);         // Assigns "Mumby" to lastName
   
// Notice the negative starting indexes...
middleName = fullName.substr(-9, 3);      // Assigns "Sid" to middleName
firstName  = fullName.substr(-16, 6);     // Assigns "Steven" to firstName
lastName   = fullName.substr(-5);         // Assigns "Mumby" to lastName

See Also

String.slice( ), String.substring( ); "Combining String Examination with Substring Extraction," and "The substr( ) function," in Chapter 4

Table of Contents