本文实例讲述了PHP+JS三级菜单联动菜单实现方法。分享给大家供大家参考，具体如下：

智能递归菜单-读取数据库

TD { FONT-FAMILY: "Verdana", "宋体"; FONT-SIZE: 12px; LINE-HEIGHT: 130%;

letter-spacing:1px } A:link { COLOR: #990000; FONT-FAMILY: "Verdana", "宋体";

FONT-SIZE: 12px; TEXT-DECORATION: none; letter-spacing:1px } A:visited

{ COLOR: #990000; FONT-FAMILY: "Verdana", "宋体"; FONT-SIZE: 12px; TEXT-DECORATION:

none; letter-spacing:1px } A:active { COLOR: #990000; FONT-FAMILY: "Verdana",

"宋体"; FONT-SIZE: 12px; TEXT-DECORATION: none; letter-spacing:1px } A:hover

{ COLOR: #ff0000; FONT-FAMILY: "Verdana", "宋体"; FONT-SIZE: 12px; TEXT-DECORATION:

underline; letter-spacing:1px } .Menu { COLOR:#000000; FONT-FAMILY: "Verdana",

"宋体"; FONT-SIZE: 12px; CURSOR: hand }

function ShowMenu(MenuID) {

if (MenuID.style.display == "none") {

MenuID.style.display = "";

} else {

MenuID.style.display = "none";

}

}

// $Id:$

//基本变量设置

$GLOBALS["ID"] = 1;

//用来跟踪下拉菜单的ID号 $layer=1;

//用来跟踪当前菜单的级数

//连接数据库

$Con=mysql_connect( "localhost", "root", "123456"); mysql_select_db(

"menu");

//提取一级菜单

$sql="select * from menu where parent_id=0" ;

$result=mysql_query($sql,$Con);

//如果一级菜单存在则开始菜单的显示

if(mysql_num_rows($result)>0) ShowTreeMenu($Con, $result, $layer, $ID);

//=============================================

//显示树型菜单函数 ShowTreeMenu($con,$result,$layer) //$con：数据库连接

//$result：需要显示的菜单记录集

//layer：需要显示的菜单的级数

//=============================================

function

ShowTreeMenu($Con, $result, $layer) {

//取得需要显示的菜单的项目数

$numrows=mysql_num_rows($result);

//开始显示菜单，每个子菜单都用一个表格来表示 echo "

< tablecellpadding = '0'cellspacing = '0'border = '0' > "; for($rows=0;$rows

//提取菜单项目的子菜单记录集 $sql="select * frommenuwhereparent_id = $menu[id]" ; $result_sub=mysql_query($sql,$Con);

echo " < tr > "; //如果该菜单项目有子菜单，则添加JavaScript onClick语句 if(mysql_num_rows($result_sub)>

0) { echo " < tdwidth = '20' > < imgsrc = 'tree_expand.gif'border = '0' > < / td > "; echo " < tdclass = 'Menu'onClick = 'javascript:ShowMenu(Menu".$GLOBALS["ID"].");' > "; } else { echo " < tdwidth = '20' > < imgsrc = 'tree_collapse.gif'border = '0' > < / td > "; echo " < tdclass = 'Menu' > "; } //如果该菜单项目没有子菜单，并指定了超级连接地址，则指定为超级连接， //否则只显示菜单名称 if($menu[url]!="")

echo " < ahref = '$menu[url]' > $menu[name] < / a > "; else echo $menu[name]; echo " < / td > < / tr > "; //如果该菜单项目有子菜单，则显示子菜单 if(mysql_num_rows($result_sub)>0) { //指定该子菜单的ID和style，以便和onClick语句相对应

echo " < trid = Menu".$GLOBALS["ID "]++ . " style='display:none'>";

echo "

";

echo "

";

//将级数加1

$layer++;

//递归调用ShowTreeMenu()函数，生成子菜单

ShowTreeMenu($Con,$result_sub,$layer);

//子菜单处理完成，返回到递归的上一层，将级数减1

$layer--;

echo "< / td > < / tr > ";

}

//继续显示下一个菜单项目

} echo " < / table > "; }

?>

$id=1 ;

function test() {

global $id; unset($id);

}

test();

echo " < fontclass = menu > ".($id). " < / font > ";

// 在 PHP 4 中这里会打印出 1

?>

$a=1 ;

$b=2 ;

function Sum() {

global $a, $b; $b=$ a + $b;

}

Sum();

echo " < fontclass = menu > ".$b. " < / font > ";

?>

希望本文所述对大家PHP程序设计有所帮助。