Javascript snippet for taking a url and updating query string paramters

Javascript: Update query param

function add_or_update_query_param(name, value, starter_url)
{
   url = starter_url || window.location.href;
   query_string_chunks = url.split("?");
   base_url = query_string_chunks[0];
   query_string = (query_string_chunks.length == 2) ? query_string_chunks[1] : null;
   chunks = [];
   new_value_updated = false;
   if (query_string)
   {
     name_value_pairs = query_string.split("&")
     for (var i = 0; i < name_value_pairs.length; i++)
     {
       pair = name_value_pairs[i].split("=");
       if (pair.length == 2)
       {
         if (pair[0].toLowerCase() === name.toLowerCase())
         {
           chunks.push(name + "=" + value);
           new_value_updated = true;
         }
         else
         {
           chunks.push(pair[0] + "=" + pair[1]);
         }
       }
     }
   }
   
   if (!new_value_updated)
   {
     chunks.push(name + "=" + value);
   }

   return (base_url + "?" + chunks.join("&"));
}