The field element may have content which is code that determines the initial value of the field.
Type: element id, must be unique in the window
A unique identifier so that you can identify the field with. You can use this as a parameter to getElementById and other DOM functions and to reference the element in style sheets.
The name of the field, which is the name that can be used via a script. For example, if a field has the name width, it can be accessed with object.width, where object is a reference to the object.
If set to true, the value of the field cannot be changed. If set to false, the field may be changed.