ActionScript for Flash MX: The Definitive Guide, Second Edition

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Chapter 5: Operators

3. If one operand is a number and the other is a string, convert the string to a num-

ber and go back to Step 1.

4. If either operand is a Boolean,

null,orundefined, convert the operand to a num-

ber and go back to Step 1.

5. If either operand is an object, invoke its valueOf() method to convert the object

to a primitive value and go back to Step 1. If the valueOf() method fails or does

not return a primitive value, return

false.

6. For any other condition, return

false.

Note that type conversions performed during a comparison do not alter the original

item’s stored value or datatype. The results of the temporary conversions are dis-

carded once the expression has been evaluated.

Here is a simple conversion example comparing two Booleans:

false < true // true: 0 is less than 1

Comparison operators always convert composite datatypes to strings or numbers for

comparison. In the following example, because both

someObj and someOtherObj are

members of the Object class, their string value, “[object Object]”, is the same:

someObj = new Object();

someOtherObj = new Object();

someObj <= someOtherObj; // true!

In contrast, the expression someObj = = someOtherObj yields false because objects are

equality-tested by reference, and they are therefore not converted to primitives dur- ...