change the border color based off a dropdown selection

The programming could be simplified if you used hierarchical field naming for all of the fields you want to control. For example, instead of using fields names of "employee_name" and "address", added a prefix of something like "HL", so the field names get changed to "HL.employee_name" and "HL.address". If you do this, the custom Validate JavaScript for the dropdown could be something like:

// Custom Validate script for dropdown

(function () {

    // Initialize some variables

    var i, aFields = [], f_prefix = "HL";

    // Create an object to associate an array of field names with each dropdown item

    var oFields = {};

    oFields["item1"] = ["field1", "field2", "field5", "field8", "field9"];

    oFields["item2"] = ["field1", "field3", "field4", "field7", "field10"];

    oFields["item3"] = ["field1", "field4", "field11", "field12", "field13"];

    oFields["item4"] = ["field1", "field2", "field3", "field4", "field5"];

    oFields["item5"] = ["field2", "field4", "field6", "field8", "field10"];

    oFields["item6"] = ["field1", "field3", "field5", "field7", "field9"];

    oFields["item7"] = ["field3", "field4", "field5", "field6", "field7"];

    // Start be resetting all of the HL field's border color to black

    getField("HL").strokeColor = color.black;

    // Set the aFields array to the array of fields corresponding to the selected dropdown item

    aFields = oFields[event.value];

    // Loop through the fields in the array and set their border color to red

    for (i = 0; i < aFields.length; i += 1) {

        getField(f_prefix + "." + aFields).strokeColor = color.red;

    }

})();

This could be improved in a number of ways, but it should get you started. Change "item1", "item2", etc, with the actual dropdown values, and "field1", "field2", etc. in each array with the field names (without the "HL" prefix) corresponding to each dropdown item.