0

我有一些代码，我现在将其粘贴在下面。代码所做的是读取 XML 文件的内容并将其放入 JSON。然后将 JSON 中的数据放入 HTML 表中。除了一件事，一切都很好。创建表格时，第一行（列标题之后）在每个单元格中始终显示为“未定义”。我浏览了这段代码，找不到任何会导致它的东西，但我不是专家，我相信一双新的眼睛会有所帮助，所以有什么想法吗？

<html>
<head>
<h1><u>USA State Information</u></h1>
</head>
<body>
<p><b>Please select an area of the USA in the dropdown list below.</b></p>
<p><select name="area" onchange="findXML(this.value)">

<?php
//set directory and open it
$xmldir = 'XML';
$dir = opendir($xmldir);

//create array and read through files in directory
$xmlfiles = array();
while ($file = readdir($dir))
{
    //if the first char is not '.' then add to array
    if (substr($file,-1,1) !== ".")
    {
        $xmlfiles[] = $file;
    }
    else
    {
        //do nothing
    }
}

echo '<option value="select">Select</option>';

foreach($xmlfiles as $area){ 
    echo '<option value="'.$area.'">'.$area.'</option>'; 
}
echo '</select>';

//close directory
closedir($dir);
?>
</p>
<p>
<div id=tbl>
</div>
<table id="elems" border="1" cellspacing="1" cellpadding="5">
<tr>
<td><b>Name</></td>
<td><b>Number</></td>
<td><b>Joined</></td>
<td><b>Population</></td>
</tr>
</table>
<script>
function findXML($area) {
$area = "XML/" + $area;
if (window.XMLHttpRequest)
{// code for IE7+, Firefox, Chrome, Opera, Safari
    xmlhttp=new XMLHttpRequest();
}
else
{// code for IE6, IE5
    xmlhttp=new ActiveXObject("Microsoft.XMLHTTP");
}
xmlhttp.open("GET",$area,true);
xmlhttp.send();
xmlDoc=xmlhttp.responseXML;
//find number of elements in the XML file
$length = xmlDoc.getElementsByTagName("name").length;

var JSONObject = [{}];
for (i=0; i!=$length; i++){
    //do something

    JSONObject.push(
    { "name":(xmlDoc.getElementsByTagName("name")[i].childNodes[0].nodeValue),
    "number":(xmlDoc.getElementsByTagName("number")[i].childNodes[0].nodeValue), 
    "joined":(xmlDoc.getElementsByTagName("joined")[i].childNodes[0].nodeValue),
    "population":(xmlDoc.getElementsByTagName("population")[i].childNodes[0].nodeValue) }
    );
}

r=1;
i=0;
for (i=0; i!=($length); i++){

    var tblr = document.getElementById("elems").insertRow(r);
    var cell1= tblr.insertCell(0);
    var cell2= tblr.insertCell(1);
    var cell3= tblr.insertCell(2);
    var cell4= tblr.insertCell(3);
    cell1.innerHTML = JSONObject[i].name;
    cell2.innerHTML = JSONObject[i].number;
    cell3.innerHTML = JSONObject[i].joined;
    cell4.innerHTML = JSONObject[i].population;
    r++;
}

}
</script>
</p>

</table>
</body>
</html>
4

2 回答 2

2

我想我发现了问题：

var JSONObject = [{}];

应该

var JSONObject = [];

The reason this fixes the issue is that you're iterating through the JSONObject array starting at the first index. This is fine, but the way you initialized the array gives the first index an empty object. When you go to get the properties name, number, etc., the empty object won't have them and they'll be returned as undefined.

于 2013-01-31T22:29:07.287 回答
0

你有没有尝试过：

对于 (i= 1 ; i!=($length); i++){

可能是您的索引从 1 而不是 0 开始

于 2013-01-31T22:27:44.430 回答