通过PHP将JQuery生成的元素连接到数据库

Question

I have a JQuery script which dynamically generates HTML elements on button click.

I am connecting to a mysql database using PDO and PHP but am wondering how you can target dynamically generated variables in an external JS file directly from PHP.

I have tried using AJAX but as far as i can understand it seems to only get data from PHP pages and not the opposite.

The JQuery code is like this...

//Where i want to use indexes from a lookup table to populate the select element

$("#main").append('<select><option value=""></option></select>'); 

I tried AJAX in this way

function getData(dataToPass)
{
    $.ajax({
        type: "POST",
        url: "getData.php",
        data: dataToPass,
        success: function (returnedData) 
        {
             $("#main").html(returnedData);
        }
    });    
}

But you cant pass variables this way can you?

Im very new to PHP and JQuery and would appreciate the help.

Answer 1

First off, PHP has nothing to do with JavaScript. They are totally different languages, in their own separate domain. They co-work however if you want to. PHP can generate JavaScript code, which will then run on the client browser. The client browser though has no idea that the JavaScript code that is running was generated by PHP. Neither does PHP have any idea how to work with a browser. PHP doesn't even have any idea about HTML.

Thus, you can't pass to PHP a complex JavaScript object, the same way as you can't pass an object from PHP to JavaScript. However you CAN pass values and data structures (arrays, data objects).

In this case, you can either get the inner HTML code of the jQuery object in your JavaScript, by running

dataToPass = {html: $("#main").html()}; //it will be a string

or by constructing an object that will have just the data you need, for example:

dataToPass = {elements: [
    {node: "select", options: [{node: "option", value: ""}]},
    {node: "input", value: "someValue", type: "text"},
]};

As you have this JavaScript, it will send this data via the script you already have, to the server. On the server side you will have to intercept the $_POST superglobal, and ask for either the HTML string, which will be $_POST['html'] if you chose the first example, or access an array of elements by $_POST['elements'] if you used the second example.