XUL - How i get the code from the open website?

hello,

i want to get the code from the open website and put the string into a variable. how i get the code?

    var x = window.content;

?

In a addon Code i found this snippet:

    var objContentWindow = gBrowser.getBrowserAtIndex(0).contentWindow;
    var objDocument = objContentWindow.document;



if i alert(objDocument) it shows [object HTMLDocument]

Is [object HTMLDocument] a dom node?

Can somebody help me?

best regards
ebody