JavaScript Prompt Box Cancel Button?

Question

I have a JavaScript function as follows:

function popup(username) {
var req = createAjaxObject();
var message = prompt(\"Message:\",\"\");
if(message != \"\"         


        

Answer 1

var message = prompt('type any...', '');
if(message+'.' == 'null.')
{
    alert("you've canceled");
}
else
{
    alert("type ok");
}