Java SE (Java Platform, Standard Edition)

I have an applet that must be loaded in a html page. this applet reads an xml file then writes the values into a new xml file.when i run my applet within the jbuilderx it performs it functions well. however if i try to load it from a html page, the applet does not respond to the mouse clicks and other events that it must do...also, i've been using javascript to call some of the functions that is publicly available. im able to call them but i can't get the value i requiered. EXAMPLE: i have a function whih returns a string. i have made a control statement that if the variable is null, then it will return an error message, else it will return the value of the variable.ive tried running it withing the jbuilderx and it worked just fine.however, if i launch it within a browser (IE6), and calls that same function using javascript, it returns me a null value, but it did not return to me the error message that must be return if the variable is null.please help...