Use:
<script src=
"http://www.java.com/js/deployJava.js"></script>
<script>
<!-- The applet id can be used to get a reference to
the applet object -->
var attributes = { id:'mathApplet',
code:'jstojava.MathApplet', width:1, height:1};
var parameters = {jnlp_href: 'math-applet.jnlp'};
deployJava.runApplet(attributes, parameters, '1.6');
</script>
参考：从 JavaScript 调用 Applet 方法 http://docs.oracle.com/javase/tutorial/deployment/applet/invokingAppletMethodsFromJavaScript.html
JavaScript 允许直接调用小程序的公共方法或公共变量。 JavaScript 将嵌入的小程序视为一个对象。通过为小程序提供 ID，JavaScript 可以通过以下方式访问它：
document.Applet_ID.Applet_Method()
你可以使用这个，
File 我的小程序.html
<html>
<head>
<script language="Javascript">
function accessAppletMethod()
{
document.getElementById("AppletABC").appendText("Applet Method");
}
</script>
<title>Testing</title>
</head>
<body onload="accessAppletMethod()">
<h1>Javascript acess Applet method</h1>
<applet width=300 height=100 id="AppletABC"
code="JavaScriptToJava.class">
</applet>
</body>
</html>
File JavaScriptToJava.java
import java.applet.Applet;
import java.awt.FlowLayout;
import java.awt.TextArea;
public class JavaScriptToJava extends Applet{
TextArea textBox;
public void init(){
setLayout(new FlowLayout());
textBox = new TextArea(5, 40);
add(textBox);
}
public void appendText(String text){
textBox.append(text);
}
}
