Compare part of string in JavaScript

Question

How do I compare a part of a string - for example if I want to compare if string A is part of string B. I would like to find out this: When string A = \"abcd\"

Answer 1

Like this:

var str = "abcdef";
if (str.indexOf("abcd") >= 0)

Note that this is case-sensitive. If you want a case-insensitive search, you can write

if (str.toLowerCase().indexOf("abcd") >= 0)

Or,

if (/abcd/i.test(str))

And a general version for a case-insensitive search, you can set strings of any case

if (stringA.toLowerCase().indexOf(stringB.toLowerCase()) >= 0)