how to convert json values in comma separated string using javascript

Answer 1

You can also look into .reduce and create a string manually

var d = [{"name":"Marine Lines","location_id":3},{"name":"Ghatkopar","location_id":2}]

var location_id_str = d.reduce(function(p, c) {
  return p ? p + ',' + c.location_id : c.location_id
},'');

console.log(location_id_str)

Answer 2

var arr = [{"name":"Marine Lines","location_id":3},{"name":"Ghatkopar","location_id":2}];

var location_array = [];
for( var i = 0; i < arr.length; i++ )
{
  location_array.push( arr[i].location_id );
}//for

var location_string = location_array.join(",");
console.log(location_string);

Note: You may need to use JSON.parse() if the arr is in string format initially.