if string contains substringjavascript code example

Example 1: javascript contains substring

var str = "We got a poop cleanup on isle 4.";
if(str.indexOf("poop") !== -1){
	alert("Not again");
}
//use indexOf (it returns position of substring or -1 if not found)

Example 2: js string contains

var string = "foo";
var substring = "oo";

console.log(string.indexOf(substring) !== -1);