how to search for a particular word in a string in javascript code example

Example 1: if str contains jquery

if (str.indexOf("Yes") >= 0)
  
  //case insensitive version
  if (str.toLowerCase().indexOf("yes") >= 0)

Example 2: js string search

var str = "This is a test sentence";
var hasTest = str.includes("test");

if(hasTest == true){
	//do a thing 
}