JSFiddle - React, Tailwind, and code Playground

by kflorence

JavaScript

// What would this result in and why?
'This is a title'.replace(' ', '_');

// What's wrong here?
var myElements = [ /* DOM Collection */ ];
for (i = 0; i < myElements.length; ++i) {
    myElements[i].onclick = function() {
        alert('You clicked on: ' + i);
    };
}

// What's wrong here?
var arr = [5, 10, 15]
var total = 1;
for (var x in arr) {
    total = total * arr[x];
}

// What is the result?
"3" - "1";
2 + "";
typeof null;
typeof [];

// Why does this result in an error?
var Car = function(color) {
    this.color = color;
};

var blueCar = Car("blue");

// What is the value of a?
var a;

// Is this valid?
undefined = "surprise!";