var number=5;
function NavF() {
var treeStyle,treePic;
    for (i=1;i<=number;i++) {
        treeStyle = document.getElementById('LM' + i);
		treePic = document.getElementById('XM' + i);
		treePic.className='nav1-out';
        treeStyle.style.display = 'none';
    }
}
 
function ShowNav(i) {
    treeStyle = document.getElementById('LM' + i);
	treePic = document.getElementById('XM' + i);
        NavF();
		treePic.className="nav1-over";
        treeStyle.style.display = '';
}