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    boolean

    The boolean function evaluates an expression and returns true or false.

    Syntax

    boolean( expression )

    Arguments

    expression
    The expression to be evaluated. The expression can refer to numbers and node-sets as well as booleans.

    Returns

    Boolean true or false after evaluating expression.

    Notes

    • A number evaluates to false if it is positive or negative zero or NaN. Otherwise, it evaluates true.
    • A node-set evaluates to true if it is non-empty.
    • A string evaluates to false if it an empty string. Otherwise, it evaluates to true.
    • An object of a type other than the four basic types is converted to a boolean in a way that is dependent on that type.

    Defined

    XPath 1.0 4.3

    Gecko support

    Supported.

    Document Tags and Contributors

    Contributors to this page: Sheppy, Fredchat, Ptak82, ethertank, Mgjbot, Jonnyq
    Last updated by: Sheppy,