function cascroll(){
	var val = 175;
	var val2 = 180;
	if (navigator.appName=="Netscape"){    	
		if(window.scrollY >= val ){
			document.getElementById('formulaire').style.marginTop = (window.scrollY - val + 10) + "px";
		}else{
			document.getElementById('formulaire').style.marginTop = "10px";
		}
		if(window.scrollY >= val2){
			document.getElementById('menu').style.marginTop = (window.scrollY - val2 + 43) + "px";
		}else{
			document.getElementById('menu').style.marginTop = "43px";
		}
	}else if (navigator.appName=="Microsoft Internet Explorer"){  
		if(document.documentElement.scrollTop >= val){
			document.getElementById('formulaire').style.marginTop = (document.documentElement.scrollTop - val + 10) + "px";
		}else{
			document.getElementById('formulaire').style.marginTop = "10px";
		}
		if(document.documentElement.scrollTop >= val2){
			document.getElementById('menu').style.marginTop = (document.documentElement.scrollTop - val2 + 43) + "px";
		}else{
			document.getElementById('menu').style.marginTop = "43px";
		}
	}
}