var s ="";
var a ="11245822.972549869,2162820.989363009,11333878.429134369,1693191.8875790108,11074604.02919112,1693191.8875790108,11245822.972549869,2162820.989363009";
var t = a.split(",");
for(var i=0; i<t.length ; i+=2){
s=s+'['+t[i]+','+t[i+1]+'],';
}
var newStr = s.substring(0, s.length-1);
var gg = '['+newStr+']';
var obj = $.parseJSON(gg);
var polygon = new esri.geometry.Polygon(new esri.SpatialReference({wkid:102100}));
polygon.addRing(obj);