let string = '30 Days Of JavaScript' console.log(string.indexOf('D')) // 3 console.log(string.indexOf('Days')) // 3 console.log(string.indexOf('days')) // -1 console.log(string.indexOf('a')) // 4 console.log(string.indexOf('JavaScript')) // 11 console.log(string.indexOf('Script')) //15 console.log(string.indexOf('script')) // -1