JSObject.call()--Applet与Javascript通讯

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本文介绍了如何使用JSObject.call()方法调用JavaScript对象的方法。该方法允许从Java环境中调用JavaScript函数，并处理参数和返回值的数据转换。

JSObject.call() Java Method

Name

JSObject.call() Java Method---invoke a method of a JavaScript object

Availability

Part of the netscape.javascript package included with Navigator 3.0

Synopsis

public Object call(String methodName, Object args[])

Arguments

methodName

The name of the JavaScript method to be invoked.

args[]

An array of Java object to be passed as arguments to the method.

Returns

A Java Object that represents the return value of the JavaScript method.

The call() method of the Java JSObject class invokes a named method of the JavaScript object represented by the JSObject. Arguments are passed to the method as an array of Java objects, and the return value of the JavaScript method is returned as a Java object. Chapter 19, LiveConnect: JavaScript and Java describes the data conversion performed to convert the method arguments from Java objects to JavaScript values and to convert the method return value from a JavaScript value to a Java object.

EG：前台获得参数，来改变panel的宽度，其中宽度在panel类里定义为全局变量。若前台设置JS参数为99或不为空，则改变size为630，否则为800.

在Applet里面，你可以这样设置代码：

try { JSObject win = JSObject.getWindow(applet); Object ret = win.call("isPreSchedule", null); if(ret != null){ this.VIEW_WIDTH = 630; }else{ this.VIEW_WIDTH = 800; } } catch (JSException e) { JOptionPane.showMessageDialog(null, e.getMessage()); e.printStackTrace(); }

其中isPreSchedule为JS文件里定义的isPreSchedule函数，或者JSP页面的SCRIPT里定义的JS函数：

function isPreSchedule(){//to resize applet for double var isCore = 99; return isCore; }