html代码：
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>Title</title>
<script src="http://cdn.bootcss.com/jquery/3.1.1/jquery.min.js"></script>
</head>
<body>
</body>
<script>
$(function () {
$.ajax({
url: "http://localhost/php/select_data.php",
type: "post",
data: {id: "id"},
dataType: "jsonp",
jsonp: "callback",//传递给请求处理程序或页面的，用以获得jsonp回调函数名的参数名(默认为:callback)
jsonpCallback: "success_jsonpCallback",//自定义的jsonp回调函数名称，默认为jQuery自动生成的随机函数名
success: function (data) {
for(let i in data){
console.log(eval("(" + data[i] + ")"))
}
},
error: function (error) {
console.log("error", error)
}
}
)
})
</script>
</html>
PHP代码：
<?php
/**
* Created by PhpStorm.
* User: DELL
* Date: 2017/12/8
* Time: 14:31
*/
$callback = isset($_REQUEST['callback']) ? trim($_REQUEST['callback']) : ''; //jsonp回调参数，必需
function getKey($key,$default=""){
return trim(isset($_REQUEST[$key])?$_REQUEST[$key]:$default);
}
$id = getKey("id");
$conn = mysqli_connect("localhost","root","","test") or die("连接失败");
$conn->query("set names utf8");
$sql = "select * from data where ".$id." is not null";
$result = $conn->query($sql);
$arr = [];
while($row=$result->fetch_assoc()){
array_push($arr,json_encode($row));
}
$json = json_encode($arr); //json 数据
echo $callback.'('.$json.')'; //返回格式，必需
效果如下：
