I created a custom field that is a drop down menu. When the user clicks on it they get the option to choose from it which password is needing reset. Based on their selection I would like for it to change the Item field to which password is needing reset. I have set up business rules that auto-assign tickets to technician groups based off the item that is being submitted. But I don't want requesters to set the item (and it's not intuitive for them versus a custom field that reads "Select which password needs reset.) 

Here is a sample script that was given to me - I can't seem to get it to work though....

var systemField = $CS.getText("ServiceReq_304_UDF_CHAR1");