Variable set catalog client script is not working

[suryareddyn]

I have created variable set ,wrote a script in catalog script and it is not working in service portal. Simple alert is not working. Please guide me If I need to make any changes global to work client script in service portal?

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[suryareddyn]

Below is the code .   Before while loop alert is working fine and the alert inside while loop is not working

function onChange(control, oldValue, newValue, isLoading) {

  if (isLoading || newValue == '') {

          return;

    }

    g_form.clearOptions('vs_location');

  var countrycode;

  // Get the country code from country table

  var gp = new GlideRecord('core_country');

  gp.addQuery('name', newValue);

  gp.query();

        alert('working');

  while(gp.next()){

    countrycode = gp.iso3166_3;

  alert('test');

  }

}

[Abhinay Erra]

On which variable is the onChange client script on and what is the variable type of it?

[suryareddyn]

Abinay ,

[suryareddyn]

[Abhinay Erra]

What is the lookup table and lookup value of the variable vs_country. Open the variable dictionary,post the screenshot of it.