var maxW=600;
//var tag=document.getElementById("dfdiv");
var imgs=document.getElementById("dfdiv").getElementsByTagName("img");
var imgslen=imgs.length;
for(var i=0;i<imgslen;i++)
{
	if(imgs[i].offsetWidth>maxW)
	{
		imgs[i].style.width=maxW+'px';
	}
}