PHP二级联动下拉菜单，带数据库表…

PHP代码

 <script language = "JavaScript">

 var onecount;

 onecount=0;

 subcat = new Array();

 <?

 mysql_connect("localhost","root","");

 mysql_select_db( "test" );

 $sql = "select * from subject";

 $result = mysql_query( $sql );

 $count = 0;

 while($res = mysql_fetch_row($result)){

 ?>

 subcat[<?=$count?>] = new Array("<?=$res[0]?>","<?=$res[1]?>","<?=$res[2]?>");

 <?

 $count++;

 }

 echo "onecount=$count;";

 ?>

 //联动函数

 function changelocation(locationid)

 {

 document.myform.ctype.length = 0;

 var locationid=locationid;

 var i;

 for (i=0;i < onecount; i++)

 {

 if (subcat[i][2] == locationid)

 {

 //var newOption1=new Option(subcat[i][1], subcat[i][0]);

 //document.all.ctype.add(newOption1);

 document.myform.ctype.options[document.myform.ctype.length] = new Option(subcat[i][1], subcat[i][0]);

 }

 }


 }

 </script>

 <form method="post" name="myform" action="ru_query.php">

 <select name="type" onChange="changelocation(document.myform.type.options[document.myform.type.selectedIndex].value)" size="1">

 <option selected value="">请指定主分类</option>


 <?

 $sql = "select * from depart";

 $result = mysql_query( $sql );

 while($res = mysql_fetch_row($result)){

 ?>

 <option value="<? echo $res[0]; ?>"><? echo $res[1]; ?></option>

 <? } ?>


 </select>


 <select name="ctype">

 <option selected value="">请指定小分类</option>

 </select>

 <input type="submit" name="Submit" value="搜索">

 </form>




 数据库是


 表depart


 departID departName


 表subject


 subjectID subjectName departID


 1.通过精选取得数据库的字段并且存入数组

 2.定义自定义函数，遍历数组并且使用echo命令把$参数转化成js可以使用的变量

 3.在js中使用<?自定义函数?>参数进行传递

 4.通过js的new Option重新组织菜单选项