jQuery 中的 Ajax 方法（节选）

$.ajax({
    url: url,                      // 地址
    data: data,                    // 参数
    type: 'POST',                  // 提交方式 可以选择 post/get 推荐 post
    async: false,                  // 同步异步
    dataType: 'json',              // 返回数据类型
    success:function(data){
        accidentList = data.list;  // 这里可以直接取 data 里面的数据了，因为设置返回值为 json 方式
    }
});

document.getElementById("search").onclick = function() { 
    var request = new XMLHttpRequest();
    request.open("GET", "server.php?number=" + document.getElementById("keyword").value);
    request.send();
    request.onreadystatechange = function() {
        if (request.readyState===4) {
            if (request.status===200) { 
                document.getElementById("searchResult").innerHTML = request.responseText;
            } else {
                alert("发生错误：" + request.status);
            }
        } 
    }
}

document.getElementById("save").onclick = function() { 
    var request = new XMLHttpRequest();
    request.open("POST", "server.php");
    var data = "name=" + document.getElementById("staffName").value 
                      + "&number=" + document.getElementById("staffNumber").value 
                      + "&sex=" + document.getElementById("staffSex").value 
                      + "&job=" + document.getElementById("staffJob").value;
    request.setRequestHeader("Content-type","application/x-www-form-urlencoded");
    request.send(data);
    request.onreadystatechange = function() {
        if (request.readyState===4) {
            if (request.status===200) { 
                document.getElementById("createResult").innerHTML = request.responseText;
            } else {
                alert("发生错误：" + request.status);
            }
        } 
    }
}

$(document).ready(function(){ 
    $("#search").click(function(){ 
        $.ajax({ 
            type: "GET",     
            url: "http://127.0.0.1:8080/ajaxdemo/serverjson2.php?number=" + $("#keyword").val(),
            dataType: "json",
            success: function(data) {
                if (data.success) { 
                    $("#searchResult").html(data.msg);
                } else {
                    $("#searchResult").html("出现错误：" + data.msg);
                }  
            },
            error: function(jqXHR){     
               alert("发生错误：" + jqXHR.status);  
            },     
        });
    });
    
    $("#save").click(function(){ 
        $.ajax({ 
            type: "POST",     
            url: "serverjson.php",
            data: {
                name: $("#staffName").val(), 
                number: $("#staffNumber").val(), 
                sex: $("#staffSex").val(), 
                job: $("#staffJob").val()
            },
            dataType: "json",
            success: function(data){
                if (data.success) { 
                    $("#createResult").html(data.msg);
                } else {
                    $("#createResult").html("出现错误：" + data.msg);
                }  
            },
            error: function(jqXHR){     
               alert("发生错误：" + jqXHR.status);  
            },     
        });
    });
});