JSFiddle - React, Tailwind, and code Playground

JavaScript

var isp = ["yahoo", "gmail"];
var yahoo = ["@yahoo.com", "@rocketmail.com", "@ymail.com"];
var gmail = ["@gmail.com"];

for(x=0;x<isp.length;x++){
    //Should alert 3 Because var yahoo contains 3 element
    //Should alert 1 because var gmail is contain 1 element
    alert(isp[x].length);
    for(y=0;y<isp[x].length;y++){
        //Should alert @yahoo.com, @rocketmail.com and so on
        alert(isp[x][y]);
    }
}