Drawing a single Polyline using SVG (See related posts)

<svg	xmlns="http://www.w3.org/2000/svg" width="100%"
		xmlns:xlink="http://www.w3.org/1999/xlink" >
  <g id="sketch" class="sketch">

    <rect x="0"
y="0" width="100%" height="100%" fill="yellow" />
  </g>

  <script>
  <![CDATA[
  var	xmlns="http://www.w3.org/2000/svg"
  Root=document.documentElement
  on_start(Root)

  function mouseUp(evt) {
	  on_pen_up(Root);
  }

  function on_start(R){
	  var Attr={
	    "onmousemove":"mouseMove",
      "onmousedown":"add_line(evt)",	
      "onmouseup":"mouseUp"
	  }
	  assignAttr(R,Attr)
  }

  function on_pen_down(R){
	  var Attr={
	    "onmousemove":"addPoint(evt)",
	    "onmouseup":"on_pen_up(Root)"
	  }
	  assignAttr(R,Attr)
  }

  function on_pen_up(R){
	  var Attr={
	    "onmousemove":"null"
	  }
	  assignAttr(R,Attr)
  }

  function add_line(evt){
	  //if (evt.target.nodeName!="rect") return
	  var C=document.createElementNS(xmlns,"polyline") 
	
	  var Attr={
		  "x":30,
		  "y":180,
		  "fill":'none',
		  "stroke": '#44a',
		  "id":'pl1',
		  "stroke-width":2
	  }
    
	  assignAttr(C,Attr)
	  Root.appendChild(C)
    
	  on_pen_down(Root)
  }

  function addPoint (evt) {
    element = document.getElementById('pl1') 	
    var point = element.ownerDocument.documentElement.createSVGPoint(); 
    point.x = evt.clientX; 
    point.y = evt.clientY;
    
    element.points.appendItem(point);
  }

  function assignAttr(O,A){
	  for (i in A) O.setAttributeNS(null,i, A[i])
  }

  ]]>
  </script>

  <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>