How to auto populate value in multi row variable set row by row.

[Chandra18]

Hi, 

For Example: In attached screenshot.There is a field "PUT Name" It have value Test, Test1, Test2. (It is a variable in catalog not MRVS). 

There is another field name is "Task input" It is multi row variable set. 

I want if I am adding a row in MRVS ,the value of put name should be auto populate in MRVS first variable which name is "security zone name" Row by row means in first row test. In second row test1 and in third row test2. 

[Chandra18]

I wrote this code on load but it is adding a blank row however, rest result are fine. 

function onLoad() {
var obj = g_form.getValue('task_input').length !== 0 ? JSON.parse(g_form.getValue('task_input')) : [];
var vofvalue = g_form.getValue('put_name');
var arry = vofvalue.split(',');

for (var i = 0; i < arry.length; i++) {
obj.push({
security_zone_name: arry[i]
});
}

g_form.setValue('task_input', JSON.stringify(obj));
}