JQuery get all elements by class name

One possible way is to use .map() method:

var all = $(".mbox").map(function() {
    return this.innerHTML;
}).get();

console.log(all.join());

DEMO: http://jsfiddle.net/Y4bHh/

N.B. Please don’t use document.write. For testing purposes console.log is the best way to go.