[SOLVED] Ajax POST variables not passing to template file

[Livusa]

Hello,

I have a strange issue that I do not seem to be able to resolve.

I have a simple form that I'd like to process via an ajax POST call using vanilla Javascript, not JQuery. However, the variables do not seem to be passing to the template file (I have an ajax_handler page for which the template file is _ajax_handler.php which is where I'm sending the call). I think I have already tried everything (including changing single quotes to double quotes -- yeah, I'm desperate) but I can't get it to work.

This is my js:

  let submit_form = document.getElementById('addToCart');
  submit_form.addEventListener('submit', updateCart);
  
  function updateCart(e) {
    e.preventDefault();

    let params = "modelId="+ document.getElementById('modelId').value + "&pieces=" + document.getElementById('pieces').value;

    let xhr = new XMLHttpRequest();
    
    xhr.onload = function() {
      if(this.status == 200) {
		//for testing purposes, only logging the response
        console.log(this.responseText);      
      }
    }
    xhr.open("POST", "/ajax_handler", true);
    xhr.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    xhr.send(params);

  }

And this is all I have in the _ajax_handler.php template file, currently responding with 'Notice: Undefined index: modelId in C:\Users\livia\source\kykdesign\site\templates\_ajax_handler.php on line 17':

echo $_POST['modelId'];

Can someone advise what I am doing wrong or what is some obvious thing that I'm missing? Some PW setting or template setting maybe?

Thanks much.

[pwired]

Coding Ajax directly in Processwire can be tricky. I always set my Ajax first up locally in plane html/php
and when I have it working there, then I port it over to Processwire. Works for me.

[Livusa]

Thanks for your reply, @pwired! I did the same ? , and in plain html/php everything works as expected.

[zoeck]

1 hour ago, Livia P said:

And this is all I have in the _ajax_handler.php template file, currently responding with 'Notice: Undefined index: modelId in C:\Users\livia\source\kykdesign\site\templates\_ajax_handler.php on line 17':

echo $_POST['modelId'];

Can someone advise what I am doing wrong or what is some obvious thing that I'm missing? Some PW setting or template setting maybe?

Can you Test it with

echo $input->post('modelId');

Or Just add an slash at the end:

xhr.open("POST", "/ajax_handler/", true);

 

[Livusa]

16 hours ago, zoeck said:

Can you Test it with

echo $input->post('modelId');

Or Just add an slash at the end:

xhr.open("POST", "/ajax_handler/", true);

 

Adding the slash to the end did it! 

Thanks much, @zoeck!