js array indexOf()
JavaScript Array indexOf() Method
HTML
<p id="demo">Click the button to display the position of the element "Apple":</p>
<button onclick="myFunction()">Try it</button>
<p><b>Note:</b>The indexOf method was introduced in JavaScript 1.6, and does not work in Internet Explorer 8 and earlier.</p>JavaScript
function myFunction()
{
var fruits = ["Banana", "Orange", "Apple", "Mango"];
if (fruits.indexOf("Apple") > 1) {
}
var x=document.getElementById("demo");
x.innerHTML=a;
}