When writing a client-side script for HTML forms, you must use the JavaScript resolveNode expression to locate nodes in the hierarchy. The script cannot walk the hierarchy using object notation. For example, the following expression is not supported:
xfa.form.subform1.TextEdit1
xfa.form.resolveNode(“subform1.TextEdit1″)
Note:
If you choose the HTML4 transformation to support Netscape Navigator 4.7.x, any JavaScript designated to run on the client is automatically run at the server instead.
See also 

Expressions supported by HTML clients