<!--[if IE]><script type="text/javascript" src="excanvas.js"></script><![endif]-->

function draw() {
      var resizeCanvas = document.getElementById("fon");
	  var lineFat = document.body.clientWidth/ 6 ;
	  var linePos =  30 ;
	  resizeCanvas.style.width = document.body.clientWidth;
	  resizeCanvas.style.height = document.body.clientHeight;
      resizeCanvas.style.position = 'fixed';
      var canvas = document.getElementById("fon").getContext('2d');
	  var a   = document.body.clientHeight;
	  var b   = document.body.clientWidth;
	  var x   = lineFat;
	  var z   = (linePos*b)/a;
	  var z1  = b*(a- 2 *x-linePos)/a;
      var z2  = b* 0 . 2 *x/a;
	  var arr = [
      [ 0 ,  0 ],// 1 
	  [b,a],// 2 
	  [b-x,a],// 3 
	  [b-x-z,a-linePos],// 4 
	  [ 0 ,a-linePos],// 5 
	  [ 0 ,a-x-linePos],// 6 
	  [z1,a-x-linePos],// 7 
      [z2,x+ 0 . 2 *x],// 8 
	  [ 0 ,x+ 0 . 2 *x],// 9 
      [ 0 , 0 ]// 10 
      ];
      canvas.beginPath();
      for (var i =  0 ; i < arr.length; i++) {
            if (i ==  0 ) canvas.moveTo(arr[i][ 0 ], arr[i][ 1 ]);
            else canvas.lineTo(arr[i][ 0 ], arr[i][ 1 ]);
      }
      canvas.fillStyle = "rgb(236,236,236)";
      canvas.fill();
}