How do you loop through the field name in javascript recordset?

Question

I'm using the following code to query a sqlite database using javascript and everything is working fine:

function getQueryRecord(tx, rs) {
                var stringResult = '';
                for(i=0;i<rs.rows.length;i++)
                {
                    r =rs.rows.item(0);
                                    $('#someting').append(r['field1'] + ' ' + r['field2']);
                }
            }

            function getUserGroup()
            {

                var db = window.openDatabase("scores", "", "Previous Scores", 1024*1000);

                db.transaction(function(tx) {
                    tx.executeSql('SELECT * FROM user_group', [], getQueryRecord);
                 });
            }

Is it possible to do something like the following in getQueryRecord to loop through all the field? If yes, what is the correct syntax?

for(k=0;k<r.fields.length;i++)
{
  $('#something').append(r[k]);
}

Thank you.

Answer 1

Have you tried the for...in syntax:

for(k in r) {
   if (r.hasOwnProperty(k))
      $('#something').append(r[k]);
}

Within the loop k will be equal to the name of the first property, then the second property, etc. (Though having said "first" and "second" the order of iteration is arbitrary.)

The if statement with .hasOwnProperty() is "optional" depending on your object structure/heirarchy: it tests whether a particular property is a "direct" property of the object or a property from somewhere up the prototype chain (noting that the for...in structure returns both types of properties). If you're not sure if you need it then you probably do.

Note: this technique applies to JavaScript objects in general, not specifically to your database objects.