There are quite a few of new features has been added in the ECMAScript 5. I thought to introducing article series describing one feature in each series.
This article describes indexOf feature of Array in ECMAScript 5.
searchElement - Search the value in the array
startIndex - Specifies the starting index of search.This is optional argument, by default startIndex is 0.
The index of the search element in the array. It returns 0 if the search element is not found.
var arr = [87, 122, 504, 9, 7, 30, 31, 76, 87, 2];
This ends the first series of ECMAScript 5.