效果演示：
安徽ID=1 parent=0
淮北ID=5 parent=1
淮溪县ID=3 parent=5
北京ID=7 parent=0
海淀ID=2 parent=7
上地ID=8 parent=2
昌平ID=4 parent=7
朝阳ID=6 parent=7
<?php
$area = array(
array('id' => 1,'name' => '安徽','parent' => 0),
array('id' => 2,'name' => '海淀','parent' => 7),
array('id' => 3,'name' => '淮溪县','parent' => 5),
array('id' => 4,'name' => '昌平','parent' => 7),
array('id' => 5,'name' =>
