asyncFunc1(function(result1) {
  asyncFunc2(result1, function(result2) {
    asyncFunc3(result2, function(result3) {
      // 更多嵌套...
    });
  });
});

function handleError(error) {
  console.error('Error:', error);
}

asyncFunc1(function(result1) {
  if (!result1) return handleError('Invalid result1');
  
  asyncFunc2(result1, function(result2) {
    if (!result2) return handleError('Invalid result2');
    
    // 继续处理...
  });
});

var total = 3;
var completed = 0;
var results = [];

function checkAllDone() {
  if (++completed === total) {
    // 所有操作完成
    console.log('All done:', results);
  }
}

asyncFunc1(function(result) {
  results[0] = result;
  checkAllDone();
});

asyncFunc2(function(result) {
  results[1] = result;
  checkAllDone();
});

asyncFunc3(function(result) {
  results[2] = result;
  checkAllDone();
});

// 使用jQuery Deferred实现多重回调
function asyncTask1() {
  var dfd = $.Deferred();
  setTimeout(function() {
    console.log('Task 1 done');
    dfd.resolve('Result from task 1');
  }, 1000);
  return dfd.promise();
}

function asyncTask2(data) {
  var dfd = $.Deferred();
  setTimeout(function() {
    console.log('Task 2 done with:', data);
    dfd.resolve('Result from task 2');
  }, 500);
  return dfd.promise();
}

// 链式调用
asyncTask1()
  .then(asyncTask2)
  .then(function(finalResult) {
    console.log('All tasks completed:', finalResult);
  })
  .fail(function(error) {
    console.error('Error occurred:', error);
  });