# Class JSObject

java.lang.Object
netscape.javascript.JSObject

public abstract class JSObject extends Object

Allows Java code to manipulate JavaScript objects.

When a JavaScript object is passed or returned to Java code, it is wrapped in an instance of `JSObject`. When a `JSObject` instance is passed to the JavaScript engine, it is unwrapped back to its original JavaScript object. The `JSObject` class provides a way to invoke JavaScript methods and examine JavaScript properties.

Any data returned from the JavaScript engine to Java is converted to Java data types. Certain data passed to the JavaScript engine is converted to JavaScript data types.

Since:
  1.5

- ## Constructor Summary

  Constructors
  Modifier
  Constructor
  Description
  `protected`
  `JSObject()`
  Constructs a new JSObject.

- ## Method Summary

  Modifier and Type
  Method
  Description
  `abstract Object`
  `call(String methodName, Object... args)`
  Calls a JavaScript method.
  `abstract Object`
  `eval(String s)`
  Evaluates a JavaScript expression.
  `abstract Object`
  `getMember(String name)`
  Retrieves a named member of a JavaScript object.
  `abstract Object`
  `getSlot(int index)`
  Retrieves an indexed member of a JavaScript object.
  `abstract void`
  `removeMember(String name)`
  Removes a named member of a JavaScript object.
  `abstract void`
  `setMember(String name, Object value)`
  Sets a named member of a JavaScript object.
  `abstract void`
  `setSlot(int index, Object value)`
  Sets an indexed member of a JavaScript object.

  ### Methods declared in class Object

  `clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait`

- ## Constructor Details

  - ### JSObject

    protected JSObject()
    Constructs a new JSObject. Users should neither call this method nor subclass JSObject.

- ## Method Details

  - ### call

    public abstract Object call(String methodName, Object... args) throws JSException
    Calls a JavaScript method. Equivalent to "this.methodName(args[0], args[1], ...)" in JavaScript.
    Parameters:
      `methodName` - The name of the JavaScript method to be invoked.
      `args` - the Java objects passed as arguments to the method.
    Returns:
      Result of the method.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### eval

    public abstract Object eval(String s) throws JSException
    Evaluates a JavaScript expression. The expression is a string of JavaScript source code which will be evaluated in the context given by "this".
    Parameters:
      `s` - The JavaScript expression.
    Returns:
      Result of the JavaScript evaluation.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### getMember

    public abstract Object getMember(String name) throws JSException
    Retrieves a named member of a JavaScript object. Equivalent to "this.name" in JavaScript.
    Parameters:
      `name` - The name of the JavaScript property to be accessed.
    Returns:
      The value of the property.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### setMember

    public abstract void setMember(String name, Object value) throws JSException
    Sets a named member of a JavaScript object. Equivalent to "this.name = value" in JavaScript.
    Parameters:
      `name` - The name of the JavaScript property to be accessed.
      `value` - The value of the property.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### removeMember

    public abstract void removeMember(String name) throws JSException
    Removes a named member of a JavaScript object. Equivalent to "delete this.name" in JavaScript.
    Parameters:
      `name` - The name of the JavaScript property to be removed.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### getSlot

    public abstract Object getSlot(int index) throws JSException
    Retrieves an indexed member of a JavaScript object. Equivalent to "this[index]" in JavaScript.
    Parameters:
      `index` - The index of the array to be accessed.
    Returns:
      The value of the indexed member.
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.

  - ### setSlot

    public abstract void setSlot(int index, Object value) throws JSException
    Sets an indexed member of a JavaScript object. Equivalent to "this[index] = value" in JavaScript.
    Parameters:
      `index` - The index of the array to be accessed.
      `value` - The value to set
    Throws:
      `JSException` - when an error is reported from the browser or JavaScript engine.