JSFiddle - React, Tailwind, and code Playground

JavaScript

function ObterDimensao(){
var img = new Image();
img.onload = function() {
  var v =  img.width + 'x' + img.height;
  teste2(v);
}
img.src = 'http://www.google.com/intl/en_ALL/images/logo.gif'
}
function teste2 (v){
alert(v);
}

ObterDimensao();