dummyimage.com Test
JavaScript
(function () {
var w = prompt("Width?");
if(!w) return;
var h = prompt("Height?");
if(!h) return;
var t = prompt("Text?");
if(t === null) return;
else if(t !== "") t = "&text=" + encodeURIComponent(t);
var location = "http://dummyimage.com/" + w + "x" + h + "/ccc/999" + t;
document.writeln("<a href='" +location + "' target='_blank'>" + location + "</a>");
})()