var jsonObj ={"list": [
  {"name":"my Name","id":12,"type":"car owner"},
  {"name":"my Name2","id":13,"type":"car owner2"},
  {"name":"my Name4","id":14,"type":"car owner3"},
  {"name":"my Name4","id":15,"type":"car owner5"}
]};
var results = [];
var searchField = "name";
var searchVal = "my Name";
for (var i=0 ; i < jsonObj.list.length ; i++)
{
  if (jsonObj.list[i][searchField] == searchVal) {
    results.push(jsonObj.list[i]);
  }
}
alert(results[0]["id"]);