－－PHP从数据库中提取内容，做不闪烁的级联菜单－－

大体思路是：先用PHP动态生成Javascript代码，再用生成的javascript执行选择功能．

１．values.php

<?php
$servername="localhost";
$dbuser="root";
$dbpassword="";
$dbname="taskmanage";
?>

２.Tdb_query.php．．．．

mysql数据库执行类：

<?php
include ("values.php");
class Tdb_query
{
 var $query_number=0;
 var $linkID;
 var $sql;
 var $result;
 function connect()
 {
  global $servername,$dbuser,$dbpassword,$dbname;
  if($this->linkID = @mysql_connect($servername,$dbuser,$dbpassword))
  {
   mysql_select_db($dbname,$this->linkID);
   return true;
  }
  else
  {
   return false;
  }
 }
 function pconnect()
 {
  global $servername,$dbuser,$dbpassword,$dbname;
  if($this->linkID = @mysql_pconnect($servername,$dbuser,$dbpassword))
  {
   mysql_select_db($dbname,$this->linkID);
   return true;
  }
  else
  {
   return false;
  }
 }
 function query($sql)
 {
  $this->query_number++;
  $this->sql = $sql;
  $this->result = mysql_query($sql,$this->linkID);
 
   return true;
  
 }
 function fetcharray()
 {
  return mysql_fetch_array($this->result);
 }
 function close()
 {
  mysql_close($this->linkID);
 }
 function queryNumbers()
 {
  return $this->query_number;
 }
 function numrows()
 {
  return mysql_num_rows($this->result);
 }
 function affectedrows()
 {
  return mysql_affected_rows($this->linkID);
 }
 function insertid()
 {
  return mysql_insert_id($this->linkID);
 }
 function result($row,$field)
 {
  return mysql_result($this->result,$row,$field);
 }
 function source()
 {
  return $this->sql;
 }
 function numFields()
 {
  return mysql_num_fields($this->result);
 }
 function errno(){
 
  return mysql_errno($this->linkID);
 }
 function fetchrows(){
  return mysql_fetch_row($this->result);
 }
}
?>
   

<SCRIPT language=javascript>
<?php
include("Tdb_query.php");

include("function.php"); 
 
$mydb=new Tdb_query;

if (!$mydb->connect()) {
   dealwitherror("dberror");
   exit();
   }
$db["depart_sql"]="select * from tvalue where type='department'";
$mydb->query($db["depart_sql"]);
while ($s=$mydb->fetcharray()) {
 $db["depart_contents"][]=$s["content"];
 $db["depart_id"][]=$s["id"];
}
if ($num=$mydb->numrows()) {
    
  
?>
cityareaname=new Array(<?php echo $num;?>);
cityareacode=new Array(<?php echo $num;?>);
 function first(preP,preC,formname,selectP,selectC)
   {
    a=0;
    <?php
    global $num;
   
    for ($i=1;$i<=$num;$i++)
   
    { $dep_res["content"]=$db["depart_contents"][$i-1];
     
     $db["zhuanye_sql"]="select * from tvalue where con_par_id=".$db["depart_id"][$i-1];
  $mydb->query($db["zhuanye_sql"]);
  if(!($mydb->numrows())){
 // echo "请先为".$dep_res["content"]."系分配专业~_~";
 // exit;
  
  }else
  {
   unset($zhuanye_contents);
     while ($r=$mydb->fetcharray()) {
      
      $zhuanye_contents[]=$r["content"];
        
       }     
     $p=$i;
     if ($i<9){$j='0'.$p;echo "if(selectP=='$j')";$f=$j;}
     else {echo "if(selectP=='$p')";$f=$p;}
     
     echo "{ a=$i;tempoption=new Option(";
     echo "'{$dep_res['content']}','$f',false,true);}";
     echo "else/n{/n";
     echo "tempoption=new Option("."'{$dep_res['content']}','$f');}/n";
  
     echo "eval('document.'+formname+'.'+preP+'.options[$i]=tempoption;');";
     $c=$i-1;
     echo "cityareacode[$c]=new Array(";
     for ($g=0;$g<$mydb->numrows()-1;$g++)
     { $m=$g+1;
      if($g<9){$m='0'.$m;}
      $xi_id=$f.$m;
      echo "'$xi_id',";
     }
     
     $m=$g+1;
     if($g<9){$m='0'.$m;}
     $xi_id=$f.$m;
     echo "'$xi_id');";
     
     
     echo "cityareaname[$c]=new Array(";
     for ($g=0;$g<$mydb->numrows()-1;$g++)
     {  $temp=$zhuanye_contents[$g];
      echo "'$temp',";
      
     }
     
     $temp=$zhuanye_contents[$g];
     echo "'$temp');";
     
    }
    }
    ?>
    
cityid=selectP;
    if (cityid!='0')
      {
        b=0;for (i=0;i<cityareaname[cityid-1].length;i++)
           {
             if (selectC==cityareacode[cityid-1][i])
               {b=i+1;tempoption=new Option(cityareaname[cityid-1][i],cityareacode[cityid-1][i],false,true);}
             else
               tempoption=new Option(cityareaname[cityid-1][i],cityareacode[cityid-1][i]);
            eval('document.'+formname+'.'+preC+'.options[i+1]=tempoption;');
           }
        eval('document.'+formname+'.'+preC+'.options[b].selected=true;');
      }
    }
 function selectcityarea(preP,preC,formname)
   {
     cityid=eval('document.'+formname+'.'+preP+'.selectedIndex;');
     j=eval('document.'+formname+'.'+preC+'.length;');
     for (i=1;i<j;i++)
        {eval('document.'+formname+'.'+preC+'.options[j-i]=null;')}
     if (cityid!="0")
       {
         for (i=0;i<cityareaname[cityid-1].length;i++)
            {
             tempoption=new Option(cityareaname[cityid-1][i],cityareacode[cityid-1][i]);
             eval('document.'+formname+'.'+preC+'.options[i+1]=tempoption;');
            }
       }
    }
</SCRIPT>
 <SCRIPT language=javascript>
first("selectp","selectc","form1",0,0);
</SCRIPT>

      <FORM
      action=file:///C|/Program%20Files/Macromedia/Dreamweaver%204/Lessons/Lesson%20Files/info_search.asp?martid=
      method=post name=form1><IMG height=6 src="" width=1><BR>
      <TABLE border=0 cellPadding=1 cellSpacing=0 width=300
        !bgcolor="#FFFDE6"><TBODY>
        <TR>
          <TD align=right class=black_con9>选择系：</TD>
          <TD class=black_con9><SELECT name=selectp
            onchange="selectcityarea('selectp','selectc','form1');"> <OPTION
              selected value=0>请选择系..</OPTION></SELECT> </TD></TR>
        <TR>
          <TD align=right class=black_con9>选择专业：</TD>
          <TD class=black_con9><SELECT name=selectc> <OPTION selected
              value=0>请选择专业..</OPTION></SELECT> </TD></TR></TBODY></TABLE></FORM>
<?php
}
?>