Using Form data in smartupdate install script

Im writing an install script for use in a JAR file. The JAR file will be on a web-page and will be downloaded automatically by smart-update in Netscape.

The problem is that I want to use data from the web-page (to be exact from a FORM) in the the install script.

Can I just use the document object in the installation script? Like this: ->

HTML page:
----------
<FORM NAME=MyFormName>
<INPUT TYPE=TEXT NAME=MyInputName Value="Hello world">
</FORM>
<SCRIPT LANGUAGE=JavaScript>
netscape.softupdate.Trigger.StartSoftwareUpdate("http://localhost/html/test.jar",trigger.FORCE_MODE);
</SCRIPT>

TEST.JAR file contains:
-----------------------
* install.js (installation script that will be fired automatically by netscape smartupdate. )
* other stuff

install.js:
-----------
MyStr = document.MyFormName.MyInputName.value ;
alert("I want to know if this works: " + MyStr)

Will this work, or is there a better/other way to pass data on to the install script?