使用JavaScript调用jQuery函数

I am using jQuery and JavaScript, I need to call the jQuery function inside my JavaScript code.

My jQuery code:

function display(id){
    $.ajax({
        type:'POST',
        url: 'ajax.php',
        data:'id='+id  ,
        success: function(data){
            $("#response").html(data);
        }//success
    }); //Ajax

    //Here I need to return the ajax.php salary
    //return ?
}

My ajax.php file has:

<?php
   session_start();
    ....

   echo "$salary";
?>

My JavaScript function has:

my.js

function showName(){
    var id = 12;

    var a = display(id); //Here I need to call the jQuery function display().
}

How do I call the jQuery function inside JavaScript code and how do I return the PHP values to jQuery?

I really think you need to separate both things:

1. A function to trigger the Ajax call.
2. A function that receive the result from the Ajax call and do whatever you need.

Like:

function display(id){
  $.ajax({
    type:'POST',
    url: 'ajax.php',
    data:'id='+id  ,
    success: anotherFunction; //Ajax response
  });
}

Then in your my.js code:

display(2);
function anotherFunction(response){
    // Here you do whatever you need to do with the response
    $("#response").html(data);
}

Remember that display() will trigger your Ajax call and the code will continue, then when you get your response (maybe some seconds or ms later) anotherFunction() will be called. That's why Ajax is asynchronous. If you need synchronous calls, check the documentation about jQuery and Ajax technique.

You call showName from the anonymous function you assigned to the key 'success' in the Ajax request. The anonymous function you assigned to success is your call back function.

Review the documentation on the Ajax class.