Client-Side JavaScript Guide

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New Features in this Release

JavaScript version 1.3 provides the following new features and enhancements:

ECMA compliance. JavaScript 1.3 is fully compatible with ECMA-262. See "JavaScript and the ECMA Specification" on page 28.

Unicode support. The Unicode character set can be used for all known encoding, and you can use the Unicode escape sequence in string literals. See "Unicode" on page 43.

New strict equality operators === and !==. The === (strict equal) operator returns true if the operands are equal and of the same type. The !== (strict not equal) operator returns true if the operands are not equal and/or not of the same type. See "Comparison Operators" on page 50.

Changes to the equality operators == and !=. The use of the == (equal) and != (not equal) operators reverts to the JavaScript 1.1 implementation. If the two operands are not of the same type, JavaScript attempts to convert the operands to an appropriate type for the comparison. See "Comparison Operators" on page 50.

Changes to the behavior of conditional tests.

You should not use simple assignments in a conditional statement; for example, do not specify the condition if(x = y). Previous JavaScript versions converted if(x = y) to if(x == y), but 1.3 generates a runtime error. See "if...else Statement" on page 80.

Any object whose value is not undefined or null, including a Boolean object whose value is false, evaluates to true when passed to a conditional statement. See "if...else Statement" on page 80.

The JavaScript console. The JavaScript console is a window that can display all JavaScript error messages. Then, when a JavaScript error occurs, the error message is directed to the JavaScript console and no dialog box appears. See Appendix B, "Displaying Errors with the JavaScript Console."

See the Client-Side JavaScript Reference for information on additional features.

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Last Updated: 05/27/99 21:21:16

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