Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
index Property

index Property

Returns the character position where the first successful match begins in a searched string.

{RegExp | reArray}.index

Arguments

RegExp
Required. The global RegExp object.
reArray
Required. An array returned by the exec method of a Regular Expression object.

Remarks

The index property is zero-based.

The initial value of the RegExp.index property is –1. Its value is read-only and changes whenever a successful match is made.

Note   The properties of the RegExp object are not available when running in fast mode, the default for JScript .NET. To compile a program from the command line that uses these properties, you must turn off the fast option by using /fast-. It is not safe to turn off the fast option in ASP.NET because of threading issues.

Example

The following example illustrates the use of the index property. This function iterates a search string and prints out the index and lastIndex values for each word in the string.

var src : String = "The rain in Spain falls mainly in the plain.";
var re : RegExp = /\w+/g;
var arr : Array;
while ((arr = re.exec(src)) != null)
   print(arr.index + "-" + arr.lastIndex + "\t" + arr);

The output of this program is:

0-3     The
4-8     rain
9-11    in
12-17   Spain
18-23   falls
24-30   mainly
31-33   in
34-37   the
38-43   plain

Requirements

Version 3

See Also

Regular Expression Syntax | exec Method

Applies To: RegExp Object

Show:
© 2015 Microsoft