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netscape.javascript.JSObject
The public final class JSObject extends Object.
java.lang.Object
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+----netscape.javascript.JSObject
JSObject allows Java to manipulate objects that are defined in JavaScript. Values passed from Java to JavaScript are converted as follows:
- JSObject is converted to the original JavaScript object.
- Any other Java object is converted to a JavaScript wrapper, which can be used to access methods and fields of the Java object. Converting this wrapper to a string will call the toString method on the original object, converting to a number will call the floatValue method if possible and fail otherwise. Converting to a boolean will try to call the booleanValue method in the same way.
- Java arrays are wrapped with a JavaScript object that understands array.length and array【索引】.
- A Java boolean is converted to a JavaScript boolean.
- Java byte, char, short, int, long, float, and double are converted to JavaScript numbers.
Values passed from JavaScript to Java are converted as follows:
- Objects that are wrappers around Java objects are unwrapped.
- Other objects are wrapped with a JSObject.
- Strings, numbers, and booleans are converted to String, Float, and Boolean objects respectively.
This means that all JavaScript values show up as some kind of java.lang.Object in Java. In order to make much use of them, you will have to cast them to the appropriate subclass of Object, as shown in the following示例:
(String) window.getMember("name")
(JSObject) window.getMember("document") Note
If you call a Java method from JavaScript, this conversion happens
automatically--you can pass in "int" argument and it works.
方法 and static方法
The netscape.javascript.JSObject class has the following methods:
表 14.1 Methods for the JSObject class
The netscape.javascript.JSObject class has the following static methods:
表 14.2 Static methods for the JSObject class
The following sections show the declaration and usage of these methods.
call
Method. Calls a JavaScript method. Equivalent to "this.methodName(args[0], args[1], ...)" in JavaScript.
Declaration
public Object call(String methodName,
Object args[])
eval
Method. Evaluates a JavaScript expression. The expression is a string of JavaScript source code which will be evaluated in the context given by "this".
Declaration
public Object eval(String s)
getMember
Method. Retrieves a named member of a JavaScript object. Equivalent to "this.name" in JavaScript.
Declaration
public Object getMember(String name)
getSlot
Method. Retrieves an indexed member of a JavaScript object. Equivalent to "this【索引】" in JavaScript.
Declaration
public Object getSlot(int index)
getWindow
Static method. Returns a JSObject for the window containing the given applet. This method is available only on the client.
Declaration
public static JSObject getWindow(Applet applet)
removeMember
Method. Removes a named member of a JavaScript object.
Declaration
public void removeMember(String name)
setMember
Method. Sets a named member of a JavaScript object. Equivalent to "this.name = value" in JavaScript.
Declaration
public void setMember(String name,
Object value)
setSlot
Method. Sets an indexed member of a JavaScript object. Equivalent to "this【索引】 = value" in JavaScript.
Declaration
public void setSlot(int index,
Object value)
toString
Method. Converts a JSObject to a String.
Overrides: toString in class Object
Declaration
public String toString()
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