function _showtree(tree_id,allnum) {
var i;
var allnumer=allnum+1;
for(i=1;i<allnumer;i++){
	document.getElementById("icon_"+i).innerText="+";
	document.getElementById("tree_class_div_"+i).style.display="none";
  }
document.getElementById("icon_"+tree_id).innerText="-";
document.getElementById("tree_class_div_"+tree_id).style.display="";
}