D-E > eval |  |

eval

eval

Availability

Flash Player 5 or later for full functionality. You can use the `eval` function when exporting to Flash Player 4, but you must use slash notation, and can only access variables, not properties or objects.

Usage

    eval(expression);

Parameters

`expression` A string containing the name of a variable, property, object, or movie clip to retrieve.

Returns

Nothing.

Description

Function; accesses variables, properties, objects, or movie clips by name. If the `expression` is a variable or a property, the value of the variable or property is returned. If the `expression` is an object or movie clip, a reference to the object or movie clip is returned. If the element named in the `expression` cannot be found, `undefined` is returned.

In Flash 4, the `eval` function was used to simulate arrays; in Flash 5, it is recommended that you use the Array object to simulate arrays.

You can also use the `eval` function to dynamically set and retrieve the value of a variable or instance name. However, you can also do this with the array access operator (`[]`).

In Macromedia Flash MX, you cannot use the `eval` function to dynamically set and retrieve the value of a variable or instance name. However, you can use the `set variable` action in Macromedia Flash 5 or Macromedia Flash MX to dynamically set and retrieve the value of a variable or instance name. For example, replace the code

    eval ("var" + i) = "first";

with this:

    set ("var" + i, "first");

Example

The following example uses the `eval` function to determine the value of the expression`` "`piece`"`+ x`. Because the result is a variable name, `piece3`, the `eval` function returns the value of the variable and assigns it to `y`:

    piece3 = "dangerous";
    x = 3;

    y = eval("piece" + x);
    trace(y);

    // Output: dangerous

See also

Array (object)