how to see if string contains substring js code example

Example 1: javascript string contains

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

console.log(string.includes(substring));

Example 2: 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)