<script src="https://code.jquery.com/jquery-3.3.1.min.js"></script>

$.ajax({
    type: "GET",
    url: "/json",
    dataType: "json",
    success: function (data) {
        // do something;
    }
});

$.get(url,data,success(response,status,xhr),dataType)

// 等价于
$.ajax({
  url: url,
  data: data,
  success: success,
  dataType: dataType
});

$.get(
    "test.cgi", 
    { name: "John", time: "2pm" },
    function(data){
    alert("Data Loaded: " + data);
  });

$.post(url,data,success(data, textStatus, jqXHR),dataType)

// 等价于
$.ajax({
  type: 'POST',
  url: url,
  data: data,
  success: success,
  dataType: dataType
});