php in resultStr 在回调jquery函数中，不起作用

Question

I have a view, the controller renders the view sending some data, example $sizes. In the view I have a jquery function that based on form post retrieves objects from database and returns a json response. in the callback function I append a resultStr so to update the view with the item I got from the database. the problem was I am using laravel and blade and blade doesn't get parsed if the script is separated from the view. So I thought, ok I will have the resultStr use plain php instead but it doesn't work either. For example I put this code in the callback function:

resultStr = resultStr +

      "<?php " +
      "foreach ($possible_sizes as $size){" +
      "print(\" {$size[\"it\"]} \")}" +
      " ?>";

$("#results").html(resultStr);

but then what I get in my div is not the data but this line:

<div id="results">

<!--?php foreach ($possible_sizes as $size){print(" {$size["it"]} ")} ?-->

</div>

question is: why?

example of code in script.js

    jQuery(function ($) {
        $(document).ready(function () {
            var form = $('form');
            form.submit(function (e) {
                e.preventDefault();
                $.ajax({
                    url: form.prop('action'),
                    type: 'post',
                    dataType: 'json',
                    data: form.serialize(),
                    success: function (data) {

                        var obj = (data);
                        var resultStr = "";
                        for (var i = 0; i < obj.length; i++) {

                            resultStr = resultStr + 
                            "string to be" + 
                            "inserted in the #results" +
                            "div and containing php code" +
                            "to be executed in the view";


                        }

                        $("#results").html(resultStr);

                    }

                })
            });

        });
    });

Answer 1

Based on the long comment thread above, it seems the answer is...

You have a PHP page which is referencing a .js file. In that separate .js file you have the following:

resultStr = resultStr +
      "<?php " +
      "foreach ($possible_sizes as $size){" +
      "print(\" {$size[\"it\"]} \")}" +
      " ?>";

$("#results").html(resultStr);

There is a series of significant problems here...

1. JavaScript runs on the client, after the server-side (PHP) code has already been processed . You can't inject more PHP code client-side because the server isn't going to process it. To the browser, this is just text. Nothing will actually execute it.
2. Even if you want to execute the PHP code before injecting its results into your HTML, .js files aren't processed by the server-side PHP interpreter. You might be able to configure that differently, but I really wouldn't recommend it. Keep the PHP in the .php pages. If you want to inject a value into the JavaScript, render that value in a script block on the page and use it to invoke functionality in the .js file.
3. Even if you do configure your server to process PHP in .js files, this PHP code is going to be one giant syntax error. JavaScript can't be used to build PHP code like this. (It can be used to build strings which look like PHP code, but in the browser those are just strings.)

PHP code is processed first, once , on the server . The results of that code are sent to the browser as a web page. From the moment the page loads in the browser, PHP is done . You can make further AJAX requests to the server to invoke further PHP operations and get the results of those operations. But you can't run PHP code in the browser .