Question

我尝试使用下面的javascript传递值

<script language= "javascript" type= "text/javascript">
var num;
function getVal()
{
num=document.getElementById('in').value;
alert(document.getElementById('parm').value);
}
</script>
<body>
<form >
Number : <input type="text" id="in"  ><br/>
<button id="myBtn" onclick="getVal()">Try it</button><br/>  
</form>
<APPLET code="Calc.class" width="100" height="100">
<PARAM name="number" id="parm">
</APPLET>

</body>    
</html>

警告框在屏幕上显示输入的值，但小程序代码未显示相同的值。我的applet代码是

public class Calc extends Applet
{

    private String strDefault = "Hello! Java Applet.";
    public void paint(Graphics g) {
    String strParameter = this.getParameter("number");
    if (strParameter == null)
    strParameter = strDefault;
    g.drawString(strParameter, 10, 10);
    }
}

有人能告诉我传递和检索param标签到html标签的值吗？

Answer 1

我认为您可以从javascript对象中指定您的参数，如下所示：

<applet code="Calc.class" width="100" height="100">
    <param name="number" id="parm" value="&{num};">
</applet>

但是，我不确定与IE的兼容性，因此您可能需要{app}代码注入相应的参数值document.write，如下所示：

<head>
    <script type="text/javascript">
        var num;

        function getVal() {
            num = document.getElementById('in').value;

            writeAppletTags();
        }

        function writeAppletTags() { 
            var container = document.getElementById("applet-container");

            container.innerHTML = "<applet code=\"Calc.class\" width=\"100\" height=\"100\">";
            container.innerHTML += "<param name=\"number\" value=\"" + num + "\">";
            container.innerHTML += "</applet>";
        }
    </script> 
</head>
<body>
    Number : <input type="text" id="in"  ><br/>
    <button id="myBtn" onclick="getVal()">Try it</button><br/>  
    <div id="applet-container" />
</body>

从Java发送POST

正如我在评论中所说，这有点复杂。您必须POST（您也可以使用GET）您的值到托管文件（可以是任何服务器端脚本技术）。以下内容对此进行了演示，code taken from here。

URL url;
URLConnection urlConnection;
DataOutputStream outStream;
DataInputStream inStream;

// Build request body
String body = "key=value";

// Create connection
url = new URL("http://myhostedurl.com/receiving-page.php");
urlConnection = url.openConnection();
((HttpURLConnection)urlConnection).setRequestMethod("POST");
urlConnection.setDoInput(true);
urlConnection.setDoOutput(true);
urlConnection.setUseCaches(false);
urlConnection.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
urlConnection.setRequestProperty("Content-Length", ""+ body.length());

// Create I/O streams
outStream = new DataOutputStream(urlConnection.getOutputStream());
inStream = new DataInputStream(urlConnection.getInputStream());

// Send request
outStream.writeBytes(body);
outStream.flush();
outStream.close();

// Close I/O streams
inStream.close();
outStream.close();

Answer 2

来自this article

的来源

例如：这是您的小程序代码：

import java.applet.*;    
import java.awt.*; 

public class DrawStringApplet extends Applet {

  private String defaultMessage = "Hello!";

  public void paint(Graphics g) {

    String inputFromPage = this.getParameter("Message");
    if (inputFromPage == null) inputFromPage = defaultMessage;
    g.drawString(inputFromPage, 50, 25);

  }

}

然后在HTML中：

<HTML>
<HEAD>
<TITLE> Draw String </TITLE>
</HEAD>

<BODY>
This is the applet:<P>
<APPLET code="DrawStringApplet" width="300" height="50">
<PARAM name="Message" value="Howdy, there!">
This page will be very boring if your 
browser doesn't understand Java.
</APPLET>
</BODY>
</HTML>

注意： DrawStringApplet是applet名称; Message是发送到applet的参数;然后，小程序将显示：Howdy, there!。

如何将值从HTML页面传递到java applet？

2 个答案: