Question: As is in the title, my question is, Is is possible to tell if the open and send methods from XMLhttpRequest actually worked? Is there any indicator? 
example code:

```
cli = new XMLHttpRequest();
cli.open('GET', 'http://example.org/products');
cli.send();

```

I'm trying to code in fault handling to this, but I need to be able to tell if the request failed so I can handle it.

Answer: 
This is an an asynchronous operation. Your script continues its execution while the request is being sent.

You detect the state changes using a callback :

```
var cli = new XMLHttpRequest();
cli.onreadystatechange = function() {
        if (cli.readyState === 4) {
            if (cli.status === 200) {
                       // OK
                       alert('response:'+cli.responseText);
                       // here you can use the result (cli.responseText)
            } else {
                       // not OK
                       alert('failure!');
            }
        }
};
cli.open('GET', 'http://example.org/products');
cli.send();
// note that you can't use the result just here due to the asynchronous nature of the request

```
```
req = new XMLHttpRequest;
req.onreadystatechange = dataLoaded;
req.open("GET","newJson2.json",true);
req.send();

function dataLoaded()
{
    if(this.readyState==4 && this.status==200)
    {
        // success
    }
    else
    {
        // io error
    }
}

```