Create and drag circles in SVG (See related posts)

<svg	xmlns="http://www.w3.org/2000/svg" width="100%"
		xmlns:xlink="http://www.w3.org/1999/xlink" >
<script><![CDATA[
var	xmlns="http://www.w3.org/2000/svg"
	xlink="http://www.w3.org/1999/xlink" 
	Root=document.documentElement
standardize(Root)

function standardize(R){
	var Attr={
		"onmouseup":"add(evt)",
		"onmousedown":"grab(evt)",
		"onmousemove":null,
		"onmouseover":"hilight(evt)",
		"onmouseout":"hilight(evt)"
	}
	assignAttr(R,Attr)
}
function hilight(evt){
	var T=evt.target
	if (T.nodeName=="rect") return
	if (evt.type=="mouseover") T.setAttributeNS(null,"stroke-opacity",1)
	else T.setAttributeNS(null,"stroke-opacity",.5)
}
function add(evt){
	if (evt.target.nodeName!="rect") return
	var C=document.createElementNS(xmlns,"circle") 
	var stroke=Color()
	var rad=10+Math.random()*50
	var Attr={
		r:rad,
		cx:evt.clientX,
		cy:evt.clientY,
		"fill": Color(),
		"fill-opacity":.75,
		"stroke": stroke,
		"stroke-opacity":.5,
		"id":stroke,
		"stroke-width":10+Math.random()*(55-rad)
	}
	assignAttr(C,Attr)
	Root.appendChild(C)
}
function grab(evt){
	var O=evt.target
	if (evt.target.nodeName=="rect") return
	var Attr={
		"onmousemove":"slide(evt,'"+O.id+"')",
		"onmouseup":"standardize(Root)"
	}
	assignAttr(Root,Attr)
}
function slide(evt,id){
	var o=document.getElementById(id)
	var c=""; if (o.nodeName=="circle") c="c"
	o.setAttributeNS(null, c+"x", evt.clientX)
	o.setAttributeNS(null, c+"y", evt.clientY)
}
function assignAttr(O,A){
	for (i in A) O.setAttributeNS(null,i, A[i])
}
function Color(){
	return "rgb("+parseInt(Math.random()*255)+","+parseInt(Math.random()*255)+","+parseInt(Math.random()*255)+")"
}
]]>
</script>
<rect width="100%" height="100%" fill="white"/>
<text font-size="12pt" x="50" y="20" id="t1">Click something to move it</text>
<text font-size="12pt" x="80" y="40" id="t2">Click nothing to add something</text>
</svg>