Flash CS3 Documentation

ActionScript 2.0 Language Reference > ActionScript language elements > Global Functions > eval function

eval function

eval(expression:Object) : Object
eval(expression:String) : Object

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

In Flash 4, eval() was used to simulate arrays; in Flash 5 or later, you should use the Array class to simulate arrays.

In Flash 4, you can also use eval() 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 Flash 5 or later, you cannot use eval() to dynamically set and retrieve the value of a variable or instance name, because you cannot useeval() on the left side of an equation. For example, replace the code

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

with this:

this["var"+i] = "first"

or this:

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

Availability: ActionScript 1.0; Flash Player 5 - 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 access only variables, not properties or objects.

Parameters

expression:Object - The name of a variable, property, object, or movie clip to retrieve. This parameter can be either a String or a direct reference to the object instance (i.e use of quotation marks (" ") is optional.)

Returns

Object - A value, reference to an object or movie clip, or undefined .

Example

The following example uses eval() to set properties for dynamically named movie clips. This ActionScript sets the _rotation property for three movie clips, called square1_mc, square2_mc, and square3_mc.

for (var i = 1; i <= 3; i++) {
 setProperty(eval("square"+i+"_mc"), _rotation, 5);
}

You can also use the following ActionScript:

for (var i = 1; i <= 3; i++) {
 this["square"+i+"_mc"]._rotation = -5;
}

See also

Array, set variable statement

Flash CS3