New Features in this Release

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New Features in this Release

JavaScript version 1.4 provides the following new features and enhancements:

Exception handling. You can throw and catch exceptions using the throw and try...catch statements. See "throw" on page 243 and "try...catch" on page 246.

New operators in and instanceof. The in operator returns true if the specified property is in the specified object; see "in" on page 269. The instanceof operator returns true if the specified object is of the specified object type; see "instanceof" on page 270.

Changes to LiveConnect. Several changes to LiveConnect improve the way Java and JavaScript code communicate:

The methods of java.lang.Object are inherited by JavaArray. In addition, the JavaArrary.toString method now calls the method java.lang.Object.toString. See "JavaArray" on page 98.

You can pass a JavaClass object to a Java method which requires an argument of type java.lang.Class instead of creating a wrapper around an instance of java.lang.Class. See "JavaClass" on page 102.

You cannot construct an instance of JSException with a detail message. The three original public constructors for the Java class netscape.javascript.JSException that supported this feature are deprecated. See "JSException" on page 280.

You cannot use the == operator to compare two instances of JSObject. Use JSObject.equals. See "Comparison Operators" on page 256 and JSObject.equals.

Changes to the eval method.

The top-level eval method cannot be called indirectly. In previous versions, it was recommended that this method not be called indirectly; starting with JavaScript 1.4, calling eval indirectly could result in a runtime error. This change improves performance. See "eval" on page 214.

The eval method is no longer available as a method of Object; use the top-level eval function instead. See "eval" on page 214.

Changes to the Function object.

You should no longer specify a function name when using the arguments array; the arguments array is a variable and is no longer a property of Function objects. This change improves performance. See "Function" on page 79 and "arguments" on page 85.

Deprecated the Function.arity property. It has been replaced by the Function.length property. See "length" on page 92.

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Last Updated: 10/29/98 20:16:58

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