PHP - 递归实现无限极联动

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递归实现无限极联动

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<?php
mysql_connect('localhost','root','aa');
mysql_select_db('php6');
mysql_query('set names utf8');
//获取所有类别
$sql='select * from category';
$rs=mysql_query($sql);
//将资源转成二维数组
$list=array();
while($rows=mysql_fetch_assoc($rs)) {
	$list[]=$rows;
}
/**
*将二维数组按树形结构显示【递归】
*@param $list array 存放所有类别的二维数组
*@param $parentid int 在数组中查找属于某个父类的子级
*@param $deep int 元素的缩进深度
*/
function createTree($list,$parentid=0,$deep=0) {
	static $tree=array();	//声明一个静态数组，这样在整个递归过程中一直存在
	foreach($list as $rows) {
		if($rows['parentid']==$parentid){
			$rows['deep']=$deep;
			$tree[]=$rows;
			createTree($list,$rows['cat_id'],$deep+1);
		}
	}
	return $tree;;
}
//测试
$array=createTree($list);
foreach($array as $rows) {
	//str_repeat()：字符串重复
	echo str_repeat('&nbsp;',$rows['deep']*20),$rows['cat_name'],'<br>';
}
?>

二级联动

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<?php
//连接数据库
mysql_connect('localhost','root','aa');
mysql_select_db('php6');
mysql_query('set names utf8');
//获取第一级
$sql="select * from category where parentid=0";
$rs1=mysql_query($sql);
?>
<select name="">
	<?php
	while($rows1=mysql_fetch_assoc($rs1)):
	?>
		<optgroup label="<?php echo $rows1['cat_name']?>">
			<?php
				$sql="select * from category where parentid=".$rows1['cat_id'];
				$rs2=mysql_query($sql);
				while($rows2=mysql_fetch_assoc($rs2)):
			?>
				<option value="<?php echo $rows2['cat_id']?>"><?php echo $rows2['cat_name']?></option>
			<?php
				endwhile;
			?>
		</optgroup>
	<?php
	endwhile;
	?>
</select>

三级联动

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<script type="text/javascript">
/*
*@param cat1 int 一级的id
*@param cat2 int 二级的id
*/
function jump(cat1,cat2) {
	location.href='?cat1='+cat1+'&cat2='+cat2;
}
</script>
<?php
	mysql_connect('localhost','root','aa');
	mysql_select_db('php6');
	mysql_query('set names utf8');

	//获取一级和二级的编号
	$cat1=isset($_GET['cat1'])?(int)$_GET['cat1']:'';	//获取传递的一级编号
	$cat2=isset($_GET['cat2'])?(int)$_GET['cat2']:'';	//获取传递的二级编号
?>
<!--一级-->
<select id="cat1" onchange='jump(this.value,"")'>
<option value="">---请选择---</option>
<?php
	$sql="select * from category where parentid=0";
	$rs=mysql_query($sql);
	while($rows=mysql_fetch_assoc($rs)):
?>
	<option value="<?php echo $rows['cat_id']?>" <?php echo $cat1==$rows['cat_id']?'selected':''?>><?php echo $rows['cat_name']?></option>
<?php
	endwhile;
?>	
</select>
<!--二级-->
<select id="cat2" onchange='jump(document.getElementById("cat1").value,this.value)'>
<option value="">---请选择---</option>
<?php
	if(isset($_GET['cat1'])):
		$sql="select * from category where parentid=$cat1";
		$rs=mysql_query($sql);
		while($rows=mysql_fetch_assoc($rs)):
?>
		<option value="<?php echo $rows['cat_id']?>" <?php echo $cat2==$rows['cat_id']?'selected':''?>><?php echo $rows['cat_name']?></option>
<?php
		endwhile;
	endif;
?>
</select>
<select id="cat3">
<option value="">---请选择---</option>
<?php
	if(!empty($_GET['cat2'])):
		$sql="select * from category where parentid=$cat2";
		$rs=mysql_query($sql);
		while($rows=mysql_fetch_assoc($rs)):
?>
		<option value="<?php echo $rows['cat_id']?>" ><?php echo $rows['cat_name']?></option>
<?php
		endwhile;
	endif;
?>
</select>