Passing properties to constructor?

Beginner question here…

Is it possible to define ‘public properties’ of an object in the constructor method when you create the object ? similar to…

var leftmain_scrollertext = new TextField({length:10});

I have a TextField and I want to set its maxChars, x, y, width etc.

when I specify one or more of these I get…
1137: Incorrect number of arguments. Expected no more than 0.

am I forced to specify each property I want individually after I have constructed it ?

Thanks