Set column transaction field as mandatory for a specific transaction form

Hi, I'm completely winging this and not getting very far. Im trying to use this standard script to set a transaction column field 'custcol_salescompldate' mandatory when a certain transaction form is being used.

So I have set this up as a User Event Script, with the Before Load Function and it applies to Sales Order


Can anyone help with adapting this?


function userEventBeforeLoad(type, form, request){

// column field example

var classFieldItemSublist = nlapiGetLineItemField('item','class');

if (classFieldItemSublist){ classFieldItemSublist.setMandatory(true);
}
}