Flash MX 2004.
document.convertToSymbol(type, name, registrationPoint)
type A string that specifies the type of symbol to create. Acceptable values are "movie clip", "button", and "graphic".
name A string that specifies the name for the new symbol, which must be unique. You can submit an empty string to have this method create a unique symbol name for you.
registration point Specifies the point that represents the 0,0 location for the symbol. Acceptable values are: "top left", "top center", "top right", "center left", "center", "center right", "bottom left", "bottom center", and "bottom right".
An object for the newly created symbol, or null if it cannot create the symbol.
Method; converts the selected Stage item(s) to a new symbol. For information on defining linkage and shared asset properties for a symbol, see Item object.
The following examples create a movie clip symbol with a specified name, a button symbol with a specified name, and a movie clip symbol with a default name:
newMc = fl.getDocumentDOM().convertToSymbol("movie clip", "mcSymbolName", "top left");
newButton = fl.getDocumentDOM().convertToSymbol("button", "btnSymbolName", "bottom right");
newClipWithDefaultName = fl.getDocumentDOM().convertToSymbol("movie clip", "", "top left");