How to make fields mandatory in ui action

[test1231998]

I have to make work notes and closed notes mandatory when I click on closed in Problem.So I have created a ui action for this.How can I add the conditions to make fields mandatory in this ui action.This is not working Can anyone please suggest and I am also not able to get the field name for work notes

[RiteshSwarnakar]

UI Action

 

Active : true

Show update : true

Client : true

List v2 Compatible : true

List v3 Compatible : true

Onclick: setM();

function setM() {

    var c = 0;
    var arr = ['fieldname1','fieldname2','variables.variablename1','variables.variablename2'];
    for (var i = 0; i < arr.length; i++) {
        if (g_form.getValue(arr[i]) == '') {
            g_form.setMandatory(arr[i], true);
            c++;
        }
    }
	
	if (c>0){
		alert('Please fill Mandatory fields');
	}

    var mrvs = g_form.getValue('mrvs_name');
    var data = JSON.parse(mrvs);
    if (data.length == 0) {
        alert('MRVS cannot be empty!');
    }

    if (c == 0 && data.length > 0)  {
        g_form.setValue('state', 'submit');
        g_form.save();
    }
}