JSObject

Summary

The public final class netscape.javascript.JSObject extends Object.

java.lang.Object
   |
   +----netscape.javascript.JSObject

Description

JavaScript objects are wrapped in an instance of the class netscape.javascript.JSObject and passed to Java. JSObject allows Java to manipulate JavaScript objects.

When a JavaScript object is sent to Java, the runtime engine creates a Java wrapper of type JSObject; when a JSObject is sent from Java to JavaScript, the runtime engine unwraps it to its original JavaScript object type. The JSObject class provides a way to invoke JavaScript methods and examine JavaScript properties.

Any JavaScript data brought into Java is converted to Java data types. When the JSObject is passed back to JavaScript, the object is unwrapped and can be used by JavaScript code. See the Core JavaScript 1.5 Guide for more information about data type conversions.

Method Summary

The netscape.javascript.JSObject class has the following methods:

call 

Calls a JavaScript method.

equals 

Determines if two JSObject objects refer to the same instance. (What's the problem with == ?)

eval 

Evaluates a JavaScript expression.

getMember 

Retrieves the value of a property of a JavaScript object.

getSlot 

Retrieves the value of an array element of a JavaScript object.

removeMember 

Removes a property of a JavaScript object.

setMember 

Sets the value of a property of a JavaScript object.

setSlot 

Sets the value of an array element of a JavaScript object.

toString 

Converts a JSObject to a string.

The netscape.javascript.JSObject class has the following static method:

getWindow 

Gets a JSObject for the window containing the given applet.

call

Method. Calls a JavaScript method. Equivalent to "this.methodName(args[0], args[1], ...)" in JavaScript.

Declaration

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

equals

Method. Determines if two JSObject objects refer to the same instance.

Overrides: equals in class java.lang.Object

Declaration

public boolean equals(Object obj)

Backward Compatibility

JavaScript 1.3. In JavaScript 1.3 and earlier versions, you can use either the equals method of java.lang.Object or the == operator to evaluate two JSObject objects.

In more recent versions, the same JSObject can appear as different Java objects. You can use the equals method to determine whether two JSObjects refer to the same instance.

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 the value of a property of a JavaScript object. Equivalent to "this.name" in JavaScript.

Declaration

public Object getMember(String name)

getSlot

Method. Retrieves the value of an array element of a JavaScript object. Equivalent to "this[index]" in JavaScript.

Declaration

public Object getSlot(int index)

getWindow

Static method. Returns a JSObject for the window containing the given applet. This method is useful in client-side JavaScript only.

Declaration

public static JSObject getWindow(Applet applet)

removeMember

Method. Removes a property of a JavaScript object.

Declaration

public void removeMember(String name)

setMember

Method. Sets the value of a property of a JavaScript object. Equivalent to "this.name = value" in JavaScript.

Declaration

public void setMember(String name,
   Object value)

setSlot

Method. Sets the value of an array element of a JavaScript object. Equivalent to "this[index] = value" in JavaScript.

Declaration

public void setSlot(int index,
   Object value)

toString

Method. Converts a JSObject to a String.

Overrides: toString in class java.lang.Object

Declaration

public String toString()