function rech_m() {
	var menu_height = document.getElementById('menu').offsetHeight;
	var content_height = document.getElementById('content_txt').offsetHeight;
	if (menu_height>content_height){
		document.getElementById('content').style.height = menu_height+20+"px";	
	}
	if (menu_height<content_height) {
		document.getElementById('content').style.height = content_height+20+"px";
	}
};