Finding a Substring in a String

1.4.finding_a_substring_in_a_string.js

// Use the String object's built-in indexOf method to find the position of the substring if it exists:

var testValue = "This is Cookbook's test string";
var subsValue = "Cookbook";

var iValue = testValue.indexOf(subsValue, 5); 
// returns index position of first character of substring, (would have returned -1 if not found)
// second parameter indicates index where search is to be started

//alternative
var iValue = testValue.lastIndexOf(subvalue, 3);
// same but in the opposite index direction (right to left)