You can use an optional parameter named "FlashVars" to pass variables into the root level of the SWF file. Place this parameter within the <OBJECT> tag or the older <EMBED> tag. All of these variables are then passed to the SWF file before the first frame of the file is played.
You can pass as many variables as you want with any variable names that you want. All browsers support FlashVars strings of up to 64 KB (65535 bytes) in length.
The format of the FlashVars property is a string that is a set of name=value pairs separated by the '&' character.
You can include special or nonprintable characters by using a '%' character followed by the appropriate two-digit hexadecimal value. A single blank space can be represented using the '+' sign. For more information about URL-encoding special characters, see URL Encoding (Wikipedia).
The following HTML code example passes two variables. The first is called "myVariable" with a value of "Hello World". The second is called "mySecondVariable" with a value of "Goodbye."