var studs = [{name: 'clap', age: 15}, 
             {name: 'martin', age: 13},
             {name: 'merry', age: 10}];

function sortbyage(a, b)
{
    //按年齡從小到大排列 
  return a.age > b.age;
}

function sortbyname(a, b)
{
  return a.name > b.name;
}

//按年齡排序 
studs.sort(sortbyage);
for(var i = 0; i < studs.length; i++)
  console.log(studs[i]);

//按姓名排序 
studs.sort(sortbyname);
for(var i = 0; i < studs.length; i++)
  console.log(studs[i]);