本文实例讲述了PHP+mysql实现的三级联动菜单功能。分享给大家供大家参考，具体如下：
数据库mysql
-- 数据库: `student`---- ------------------------------------------------------------ 表的结构 `student`--CREATE TABLE `student` ( `id` int(50) NOT NULL auto_increment, `name` varchar(50) collate utf8_unicode_ci NOT NULL, `dept` varchar(50) collate utf8_unicode_ci NOT NULL, `class` varchar(50) collate utf8_unicode_ci NOT NULL, `sex` varchar(50) collate utf8_unicode_ci NOT NULL, `dept_id` int(50) NOT NULL, `class_id` int(50) NOT NULL, PRIMARY KEY (`id`)) ENGINE=MyISAM DEFAULT CHARSET=utf8 COLLATE=utf8_unicode_ci AUTO_INCREMENT=5 ;---- 导出表中的数据 `student`--INSERT INTO `student` (`id`, `name`, `dept`, `class`, `sex`, `dept_id`, `class_id`) VALUES(1, "计算机名字", "计算机工程系", "计061", "男", 1, 11),(2, "教计名字", "计算机工程系", "教技061", "男", 1, 14),(3, "管理名字", "管理系", "管理061", "女", 2, 21),(4, "机械名字", "机械工程系", "自动化061", "男", 3, 31);
index.php代码：
<?php$link=mysql_connect("localhost","root","") or die("数据库服务器连接错误".mysql_error());mysql_select_db("student",$link) or die("数据库访问错误".mysql_error());mysql_query("set character set gb2312");mysql_query("set names gb2312");?><html> <head> <title>下拉框连动</title> </head><body><script language="JavaScript">//二级菜单数组var subcat = new Array();<?php$i=0;$sql="select * from student";$query=mysql_query($sql,$link);while($arr=mysql_fetch_array($query)){ echo "subcat[".$i++."] = new Array("".$arr["dept_id"]."","".$arr["class"]."","".$arr["class_id"]."");";}?>//三级菜单数组var subcat2 = new Array();<?php$i=0;$sql="select * from student";$query=mysql_query($sql,$link);while($arr=mysql_fetch_array($query)){ echo "subcat2[".$i++."] = new Array("".$arr["class_id"]."","".$arr["class"]."","".$arr["name"]."");";}?>function changeselect1(locationid){ document.form1.s2.length = 0; document.form1.s2.options[0] = new Option("22请选择22",""); for (i=0; i<subcat.length; i++) { if (subcat[i][0] == locationid) { document.form1.s2.options[document.form1.s2.length] = new Option(subcat[i][1], subcat[i][2]); } }}function changeselect2(locationid){ document.form1.s3.length = 0; document.form1.s3.options[0] = new Option("33请选择33",""); for (i=0; i<subcat2.length; i++) { if (subcat2[i][0] == locationid) { document.form1.s3.options[document.form1.s3.length] = new Option(subcat2[i][2], subcat2[i][0]); } }}</script>三级联动演示：<BR><form name="form1"><select name="s1" onChange="changeselect1(this.value)"><option>--请选择--</option><option value=1>计算机工程系</option><option value=2>管理系</option><option value=3>机械工程系</option></select><select name="s2" onChange="changeselect2(this.value)"> <option>--请选择--</option></select><select name="s3"> <option>--请选择--</option></select></form></body></html>更多关于PHP相关内容感兴趣的读者可查看本站专题：《php+mysql数据库操作入门教程》、《php+mysqli数据库程序设计技巧总结》、《php面向对象程序设计入门教程》、《PHP数组(Array)操作技巧大全》、《php字符串(string)用法总结》及《php常见数据库操作技巧汇总》
希望本文所述对大家PHP程序设计有所帮助。
