ActionScript 2.0 Language Reference - Adobe Help and Support

Returns
String - A string.
Example
In the following example, you use ActionScript to convert specified expressions to a string:
var string1:String = String("3");
var string2:String = String("9");
trace(string1+string2); // 39
Because both parameters are strings, the values are concatenated rather than added.
See also
toString (Number.toString method), toString (Object.toString method), String,
" string delimiter operator
substring function
substring(string:String, index:Number, count:Number) : String
Deprecated since Flash Player 5. This function was deprecated in favor of String.substr().
Extracts part of a string. This function is one-based, whereas the String object methods are
zero-based.
Availability: ActionScript 1.0; Flash Player 4
Parameters
string:String - The string from which to extract the new string.
index:Number - The number of the first character to extract.
count:Number - The number of characters to include in the extracted string, not including
the index character.
Returns
String - The extracted substring.
See also
substr (String.substr method)
110 ActionScript language elements