Event.srcelement Not Working For My Object

This is my object elobj.

elobj=el.document.frames[fIDx].document.body
elobj.onresizeend=doElResizeEnd

When some one resize image element the doElResizeEnd function
start's .But I get "Require object" error from "var el= event.srcElement;"

function doElResizeEnd()
{
var el= event.srcElement;

if( el.type=='image')
{
alert(el.name)
alert(""+el.width)
alert(""+el.height)
}

alert("doElResizeEnd");
}