Is it possible to manipulate an SVG document embedded in an HTML doc with JavaScript?

<object id="img" data="image.svg" width="500" height="300"/>
<script>document.getElementById("img").addData([1,23,4]);</script>

<script>document.method = function() {}</script>

<script>$("img").observe("load", function() {$("img").contentDocument.method()});

/****************** Track and handle SVG object movement *************/
var svgDoc;
var svgRoot;
var mover='';   	//keeps track of what I'm dragging

///start function////
//do this onload
function start(evt){
    //set up the svg document elements
    svgDoc=evt.target.ownerDocument;
    svgRoot=svgDoc.documentElement;
    //add the mousemove event to the whole thing
    svgRoot.addEventListener('mousemove',go,false);
    //do this when the mouse is released
    svgRoot.addEventListener('mouseup',releaseMouse,false);
}

// set the id of the target to drag
function setMove(id){ mover=id; }

// clear the id of the dragging object
function releaseMouse(){
    if(allowMoves == true){ sendMove(mover); }
    mover='';
}

// this is launched every mousemove on the doc
// if we are dragging something, move it
function go(evt){
    if(mover != '' && allowMoves != false) {
    	//init it
    	var me=document.getElementById(mover);

    	//actually change the location
    	moveX = evt.clientX-135; //css positioning minus 1/2 the width of the piece
    	moveY = evt.clientY-65;
    	me.setAttributeNS(null, 'x', evt.clientX-135);
    	me.setAttributeNS(null, 'y', evt.clientY-65);
    }
}

function moveThis(pieceID, x, y) {
    $(pieceID).setAttributeNS(null, 'x', x);
    $(pieceID).setAttributeNS(null, 'y', y);
}

<script type="text/javascript">
function change(){
    var s=document.getElementById("cube");
    s.setAttribute("stroke","0000FF");
}
</script>

<svg width=100 height=100 style='float: left;'>
  <rect x="10" y="10" width="60" height="60" id="cube" onclick="change()" stroke=#F53F0C stroke-width=10 fill=#F5C60C />
</svg>

<button onclick="change()">Click</button>