Request.YQLajax = new Class({
    // gets basic info such as country and latitude data
    Extends: Request.JSONP,
    options: {
        log: !true,
        url: "http://query.yahooapis.com/v1/public/yql?q=select%20*%20from%20html%20where%20url%3D%22{location}%22&format=xml"
    },
    initialize: function(location, options) {
        this.parent(options);
        if (!location)
            return;
            
        this.options.url = this.options.url.substitute({location: encodeURIComponent(location)});
    },
    success: function(data, script) {
        this.parent(data, script);
    }
});

$("fetch").addEvents({
    click: function() {
        new Request.YQLajax("http://www.bbc.co.uk/", {
            onSuccess: function(data) {
                $("result").set("html", data.results);
            }
        }).send();        
    }
});

<div id="result"></div>
<div id="fetch">click to fetch from bbc.co.uk</div>

#fetch {
    border: 1px solid #000;
    cursor: pointer;
    _cursor: hand;
}

MooShell