get looping in jquery

var obj = {
  "flammable": "inflammable",
  "duh": "no duh"
};
$.each( obj, function( key, value ) {
  alert( key + ": " + value );
});
//Array
$.each( arr, function( index, value ){
    sum += value;
});

//Object
$.each( obj, function( key, value ) {
    sum += value;
});