I'm getting the following exception while making a call using XMLHttp object asynchronously in Mozilla Firefox.

```
407 Proxy Authentication Required
The ISA Server requires authorization to fulfill the request.
Access to the Web Proxy filter is denied.

```

### Description of cause:

Actually I'm trying to make an asynchronous request to using get in javascript. It is working fine using IE 6 but for IE 7 and Firefox 3.5, it will it won't get any data using asynchronous request so how to overcome this problem?

When I debug in Firefox 3.5 using firebug it shows 

```
407 Proxy Authentication Required The ISA Server requires authorization to fulfil the request. Access to the Web Proxy filter is denied.

```

exception at console so how to tackle this issue

Note: our network has proxy server