html+js+PHP(使用了smarty模板技术)+mysql实现二级动态下拉列表(select)
目标
需要的是在选择第一个select下拉列表后,将选择的内容传送到PHP页面。在PHP页面中通过查询数库,得到第二个select需要显示的option的值,并在select中显示。
方案
1 利用ajax上传数据到PHP,由于利用了smarty模板技术,可以直接给模板中的变量赋值,这样就可以不用通过ajax接收返回值再经过处理输出了。
由于这个PHP页面没有包含在其他PHP页面里,是独立的。这样就造成无法赋值。
2 通过ajax接收返回值,这里的返回值就是以上数据库查询的结果。
通过json_encode()将其转化为json格式,然后输出。
js中将responseText字符串转化为json格式??JSON.parse()函数实现。
遍历数组,并添加option给select。
本次使用的是方案2
部分代码
JS代码:
function get_value(form){ var scid=sub_class.value;//运算类型号//---------------------------------------//使用ajax发送选中的运算类 var url = "query_subject.php?scid="+scid; xmlhttp.onreadystatechange = Content;// var url = "query_subject.php?"; xmlhttp.open("GET",url,true); xmlhttp.send(null);//--------------------------------------- function Content(){ if(xmlhttp.readyState==4){ if(xmlhttp.status==200){ var sel=document.getElementById("sub_name"); var rst=JSON.parse(xmlhttp.responseText);//将字符串转化为数组 for(var i=0; i<rst.length i var opt="document.createElement('option');" opt.value="rst[i].sid;" opt.text="rst[i].s_name;" try sel.add standards compliant catch ie only else alert> <p class="sycode"> <br> </p> PHP代码: <p class="sycode"> </p> <pre name="code" class="sycode">?phpheader ( "Content-type: text/html; charset=UTF-8" ); //设置文件编码格式require_once("system/system.inc.php"); //包含配置文件$scid=$_GET['scid'];$rst=null;if($scid){ $sql="select sid, s_name from subject where scid='$scid'"; $rst=$admindb->ExecSQL($sql, $conn);}echo(json_encode($rst));?>

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