Edit in JSFiddle

//Searching for a substring


document.getElementById("result").innerHTML =  "Widget with id".includes("Widget").toString();

document.getElementById("result").innerHTML += '<br />';

document.getElementById("result").innerHTML += "Hello".includes("Bye");

document.getElementById("result").innerHTML += '<br />';


document.getElementById("result").innerHTML += "Widget".includes("id", 3);

document.getElementById("result").innerHTML += '<br />';

<h1>String</h1>

<h2>Searching for a substring</h2>

<blockquote>
"Widget with id"=="Widget"<br />
"Hello"!="Bye"<br />
"Widget"="id",3<br />
result:<br />
<span id="result"></span>
</blockquote>