javascript is element is in array code example
Example 1: javascript element in array
var fruits = ["Banana", "Orange", "Apple", "Mango"];
var n = fruits.includes("Mango");
Example 2: javascript check if in array
var extensions = ["image/jpeg","image/png","image/gif"];
if(extensions.indexOf("myfiletype") === -1){
alert("Image must be .png, .jpg or .gif");
}