ActionScript for Flash MX: The Definitive Guide, Second Edition

String.indexOf() Method

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See Also

String.charCodeAt(); “The fromCharCode() function,” in Chapter 4; Appendix B

String.indexOf() Method

find the first occurrence of a substring in a string

Flash 5

string.indexOf(substring)

string.indexOf(substring, startIndex)

Arguments

substring A string containing the character or characters for which to search.

startIndex An optional integer position in

string at which to start searching for

substring. Should be in the range of 0 (the first character) to string.length – 1

(the last character). Defaults to 0.

Returns

The position of the first occurrence of substring in string (starting at startIndex). Returns

–1 if

substring is not found at or after startIndex in string.

Description

The indexOf() method is used to search for characters in strings or to check whether a

string contains a certain substring. The search is case-sensitive. Use toLowerCase() to

ensure a case-neutral search, as shown in the third Example.

Example

// Check if an email address contains an @ sign

var email = "derekaol.com";

if (email.indexOf("@") = = -1) {

trace("This isn't a valid email address");

}

// Check if an email address has an @ sign and is from the domain aol.com

var email = "[e-mail]";

var atPos = email.indexOf("@");

if (atPos != -1 && email.indexOf("aol.com") ...