php 无限级分类，超级简单的无限级分类，支持输出树状图

<"<option value=\$id \$select>\$spacer\$name</option>"
   * @param $sid 被选中的ID, 比如在做树形下拉框的时候需要用到
   * @param $adds
   * @param $str_group
   */
  function get_tree($myid, $str, $sid = 0, $adds = '', $str_group = '')
  {
    $number=1;
    $child = $this->get_child($myid);
    if(is_array($child)) {
      $total = count($child);
      foreach($child as $id=>$a) {
        $j=$k='';
        if($number==$total) {
          $j .= $this->icon[2];
        } else {
          $j .= $this->icon[1];
          $k = $adds "\$nstr = \"$str_group\";") : eval("\$nstr = \"$str\";");
        $this->ret .= $nstr;
        $this->get_tree($id, $str, $sid, $adds.$k.'&nbsp;',$str_group);
        $number++;
      }
    }
    return $this->ret;
  }
 
  /**
  * 同上一方法类似,但允许多选
  */
  function get_tree_multi($myid, $str, $sid = 0, $adds = '')
  {
    $number=1;
    $child = $this->get_child($myid);
    if(is_array($child))
    {
      $total = count($child);
      foreach($child as $id=>$a)
      {
        $j=$k='';
        if($number==$total)
        {
          $j .= $this->icon[2];
        }
        else
        {
          $j .= $this->icon[1];
          $k = $adds "\$nstr = \"$str\";");
        $this->ret .= $nstr;
        $this->get_tree_multi($id, $str, $sid, $adds.$k.'&nbsp;');
        $number++;
      }
    }
    return $this->ret;
  }
 
  function have($list,$item){
    return(strpos(',,'.$list.',',','.$item.','));
  }
 
  /**
   +------------------------------------------------
   * 格式化数组
   +------------------------------------------------
   * @author abc
   +------------------------------------------------
   */
  function getArray($myid=0, $sid=0, $adds='')
  {
    $number=1;
    $child = $this->get_child($myid);
    if(is_array($child)) {
      $total = count($child);
      foreach($child as $id=>$a) {
        $j=$k='';
        if($number==$total) {
          $j .= $this->icon[2];
        } else {
          $j .= $this->icon[1];
          $k = $adds "tree">'; 
$str = "<option value=\$id \$select>\$spacer\$name</option>"; 
$html .= $tree->get_tree(0,$str,-1).'</select>'; 
echo $html; 
?>