var agt=navigator.userAgent.toLowerCase();
var is_nav  = ((agt.indexOf('mozilla')!=-1) && (agt.indexOf('spoofer')==-1) 
               && (agt.indexOf('compatible') == -1) && (agt.indexOf('opera')==-1) 
               && (agt.indexOf('webtv')==-1));
var is_major = parseInt(navigator.appVersion);
var is_opera = (agt.indexOf("opera") != -1);
var not_nav6 = (is_nav && (is_major < 5));
var isNN=(navigator.appName=="Netscape");

var my_height;
//detect height
function detect_height(){
	if(isNN){
		if(not_nav6){
			my_height=window.innerHeight+5;
		}else{
			my_height=window.innerHeight;
		}
	}else if(is_opera){
		my_height=window.innerHeight;
	}else{
		//my_height=window.document.body.clientHeight();
		my_height=window.document.body.offsetHeight;
	}
	//alert(my_height);
}