javascript - php代码在文本框更改事件上显示null

Question

下面我放置了完整的代码..

我正在文本框的 keydown 事件中填充另一个文本框中的值..

一切都工作正常...

但我的问题是如何在从按键事件填充的所有文本框中返回 0...如果按键事件为空。

Bcoz，当我尝试将某些值编辑为 null 时，另一个文本框值保持原样...

customerdata.php页面代码

<?php
require_once('includes/config.php');
$q = $_GET['q'];
$city = $database->getRows("SELECT HM.id AS hawkerid,HM.mobile As hawkermobile,CM.id AS subagentid,CM.tehsil AS Centername,CM.subagentname As subagentname FROM hawker_master HM inner join sub_agent_master CM on CM.id = HM.subagentname WHERE hawker_name = :hawker_name", array(':hawker_name'=>"$q"));  
$info = array();
foreach($city as $row)
{
    $cID = $row['id'];
    $cName = $row['subagentname'];      
    $hawid = $row['hawkerid'];  
    $subid = $row['subagentid'];    

    $info[] = array('name' => $cName,'hid' => $hawid,'sid' => $subid);
}
echo json_encode($info);
?>

下面是我的 JavaScript

<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.10.1/jquery.min.js" type="text/javascript"></script>
<script>
function show(str)
{
if (str=="")
{
    document.getElementByName("hawkername").value="";
    return;
}
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.onreadystatechange=function()
{
    if (xmlhttp.readyState==4 && xmlhttp.status==200)
    {
        var data = JSON.parse(xmlhttp.responseText);
        for(var i=0;i<data.length;i++) 
        {         
          document.getElementById("subagentname").value = data[i].name;
          document.getElementById("hawkernum").value = data[i].hid; 
          document.getElementById("subagentnum").value = data[i].sid;    
        }
    }
}
xmlhttp.open("GET","customerdata.php?q="+str,true);
xmlhttp.send();
}
</script>

我的文本框显示代码

<input id="hawker_name" onKeyDown="show(this.value)" value="<?php echo $data['hawker'];?>"  />
<input  type="" id="hawkernum" value="<?php echo $data['hawkerid'];?>"  name="hawkername" />

Answer 1

使用 getElementById 获取 id hawkernum 在 Javascript 中更改此部分。

if (!str || str.trim().length <= 0)
{
    document.getElementById("hawkernum").value="";
    return;
}

并声明输入类型

<input  type="text" id="hawkernum" value="<?php echo $data['hawkerid'];?>"  name="hawkername" />