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我正在运行以下代码。该按钮基本上将图表添加到 html 页面中。我面临的问题是：当我第二次单击按钮时，前一个图表的曲线消失了（尽管标签没有），我希望它保持不变。我尝试调试，当我在 buttonClicked javascript 函数的开头修改 innerHTML 属性时，就会发生这种情况。谁能告诉我为什么会这样？

<html>
<head>
<title>Configurando gráficos</title>
<script language="javascript" type="text/javascript" src="../scripts/jquery.js"></script>
<script language="javascript" type="text/javascript" src="../scripts/jquery.flot.js"></script>
<script type="text/javascript" language="javascript">

var id = 0;

function requestGraph(placeholder) {
  $.ajax({url: "../requests/get_xml_oid.php?oid=1.3.6.1.2.1.2.2.1.10.65540&host=200.234.199.161", success: function(request){
        // Initialize dataToDraw to an empty array
        var dataToDraw = [];

        // The first tag is called ifInOctets      
        var ifInOctetsEl = request.getElementsByTagName("ifInOctets")[0];

        // Store the data element, to loop over the time-value pairs      
        var dataEl = ifInOctetsEl.getElementsByTagName("data");

        // For each data element, except the first one
        var i;
        for (i=1; i<dataEl.length; i++){
            // get the time-value pair
            var timeEl = dataEl[i].getElementsByTagName("time")[0];
            var valueEl = dataEl[i].getElementsByTagName("value")[0];
            var time = timeEl.textContent;
            var value = valueEl.textContent;

            // get the value of the former data element
            // Warning: the former value in the XML file is newer than the latter
            var formerValueEl = dataEl[i-1].getElementsByTagName("value")[0];
            var formerValue = formerValueEl.textContent;

            // push to the dataToDraw array
            dataToDraw.push( [parseInt(time)*1000, parseInt(formerValue) - parseInt(value)]);

        }

        // tell the chart that the x axis is a time variable
        var options = {
            xaxis: { mode: "time"}
        };

        // plot the chart and place it into the placeholder
        jQuery.plot(jQuery(placeholder), [dataToDraw], options);

      }});
}
function buttonClicked() {
    document.getElementById("body").innerHTML += "<div id=\"placeholder" + id + "\" style=\"width:600px;height:300px;\"></div>";
    requestGraph("#placeholder" + id);
    setInterval("requestGraph(\"#placeholder" + id + "\")",60000);
    id = id + 1;
}

</script>
</head>
<body id="body">
<button type="button" onClick="buttonClicked()">Click Me!</button>
</body>
</html>
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1 回答 1

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根据this previous question，分配给innerHTML会破坏子元素。我不清楚这正是您所看到的，但也许document.createElement按照类似问题中的建议使用也对您有用。

于 2010-03-05T19:15:27.117 回答