EASY Question - I'm embarrased to ask!

programming flash
1

Hey People, I have a simple project, but one part is giving me problems. The entire code is as follows. Everything works except for the [COLOR=Red]Bold & Red part[/COLOR]. Any thoughts? The FLA is here: http://www.sergprotector.com/temp/focalConsole.fla.

function setVariables(){
xVar=35;
yVar=18;
zVar=0;
[COLOR=Red]xVar.maxChars = 4;
xVar.restrict = “0123456789.”;[/COLOR]
}
setVariables();
convertButton.onRelease = function(){
zVar = 35/xVar * yVar;
}