Calling a JS function from PHP

Question

I'm making a site with several calls to PHP via AJAX, right now AJAX uses POST to get a echoed string from PHP and then compares that in a switch and then does what is required. Example in the code below

function submitPHP(dataForPHP){
    //Runs ajax request
    $.ajax({
        type : "POST",
        url : 'initPHP.php',
        dataType : 'text',
        data : dataForPHP,
        success : function(data){
            //Checks echoed data from PHP
            switch(data){
                case "LOGIN_ACCEPTED":
                    loggedInFunction();
                    break;
                case "LOGIN_FAILED":
                    loggedInFailedFunction();
                    break;
            }
        }
    });
}

I'm thinking if there is a way for the PHP to return what function (like "loggedInFunction();") I want to call instead of a string that I then have to compare and then call the function? I can change the AJAX to use JSON instead if that does it.

I've been looking around on other similar questions here on stack on most of them want to echo a whole function which is not what I want to do.

Thanks in advance!

I think that what you want to do is JSONP: https://stackoverflow.com/a/3840118/4949918 — Axnyff, Jun 11 '17 at 10:29
I think [this](https://stackoverflow.com/questions/912596/how-to-turn-a-string-into-a-javascript-function-call) might be what you are looking for. I find it a bit odd that you want to so tightly couple the back- and front-end, but it is possible. Last word of advice: don't go down the `eval` route. There be dragons. — Nelewout, Jun 11 '17 at 10:34
You don't want to do, what you want to do. It's not of the buisness of PHP to even know what function to be called in JS, nor is it the buisness of JS to tell PHP wich functions to use. Keep them sepearted and use an interface for the communication between the two ends, or you'll end up having to debug PHP because you've changed something in JS and vice versa — Thomas, Jun 11 '17 at 10:34

score 0 · Answer 1 · answered Jun 11 '17 at 11:47

I'd do this.

use HTTPS to perform login, HTTP really is insecure nowadays;
create a controller object with all allowed methods (actions);
call an action of that controller.

The idea of having a controller is convenient on several levels:

security: if a method is not in the controller you cannot call it, so it is a way to know what can be called and what is absolutely not possible to call;
cohesion: the methods are all next to each other and easier to maintain;
encapsulation: if there is any state it can be held easily inside the context of that object.

This is an example:

loginController = {
  "acceptAction": function () {
  },
  "failAction": function () {
  }
};

You can now call those methods from the AJAX handler. Say the server tells you what you must do. A verb so to speak, such as accept or fail. You can then do:

"success": function (data) {
  loginController[data + "Action"]();
}

And that's it.

BTW: this is just the very basic MVC pattern. Oldie but goldie :)

Calling a JS function from PHP

1 Answers1