how to correctly write php inside javascript

Question

Good afternoon..
I have the following situation:

<?php

    $array_dias_da_semana = array("domingo", "segunda", "terca","quarta","quinta","sexta","sabado"); 
    $zebra = 'domingo';
?>

    $(function()
        {
            $('.button').click(function()
            {
                bb = $(this);
                $(".tab-content div").each(function( index ) 
                {
                    if($( this ).attr('class').indexOf('active') != -1)
                    {               
                        var vdia =  "<?php echo $array_dias_da_semana[index]?>";


                        alert(" B Indice: " + index+ ' value..: '+ $(bb).val()+ ' - vdia ' + vdia);

                    }
                });
            });
        });

I can’t spell this line correctly:

var vdia =  "<?php echo $array_dias_da_semana[index]?>";

How should I write?????
I have the PHP ARRAY that contains 6 dates and the javascript function that returns the tab index. In the line above as you can see the index is the return of Function.
With the index I would like to get the date in the corresponding PHP ARRAY Indice $array_dias_da_week

Answer 1

PHP does not communicate directly with the front-end, index is a variable of Javascript and not PHP, so PHP has already been processed and has already been executed, PHP will search index as if it were a constant in PHP.

In other words, there is no way to do this, similar to what I have already answered in:

• /a/177050/3635
• /a/168915/3635

You have to understand some things first:

• front-end

  The front-end is a relative term, but in practice it is usually used to refer to what will be processed in the browser

• back-end

  The back-end is also relative, but in practice it is usually used to refer to general server-side technologies such as database, HTTP-processing program (such as Apache and IIS) and dynamic language and frameworks

HTTP is about this:

You will need to change the approach

Answer 2

The right way to write PHP within Javascript is to avoid doing so. I know it sounds like a joke but it’s true. I used these language mixes myself but this generates a huge amount of bugs and is difficult to read and maintain.

If you need to pass PHP information to Javascript, create as few contact points as possible. In this case you would pass this array at the beginning.

In PHP:

<?php
    $array_dias_da_semana = array("domingo", "segunda", "terca","quarta","quinta","sexta","sabado"); 
    $zebra = 'domingo';
?>

In Javascript (with php in a single line, at the beginning):

$(function() {
  var diasDaSemana = <?php echo json_encode($array_dias_da_semana); ?>;
  // assim a tua variável diasDaSemana fica ["domingo","segunda","terca","quarta","quinta","sexta","sabado"]
  $('.button').click(function() {
    $(".tab-content div").each(function(index) {
      if (this.classList.contains('active')) {
        var vdia = diasDaSemana[i];

        alert(" B Indice: " + index + ' value..: ' + this.value + ' - vdia ' + vdia);

      }
    });
  });
});