index Property

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


The object associated with this property is always the global RegExp object.


The index property is zero-based. The initial value of the index property is –1. Its value changes whenever a successful match is made.


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.

function RegExpTest(){
  var ver = Number(ScriptEngineMajorVersion() + "." + ScriptEngineMinorVersion())
  if (ver >= 5.5){
    var src = "The rain in Spain falls mainly in the plain.";
    var re = /\w+/g;
    var arr;
    while ((arr = re.exec(src)) != null)
       print(arr.index + "-" + arr.lastIndex + "\t" + arr);
    alert("You need a newer version of JScript for this to work");


Version 3

See Also

RegExp Object Properties | Regular Expression Syntax

Applies To: RegExp Object