Insert php in javascript inside echo

Question

I have my Javascript inside echo, but i want it to have a php also inside. I dont know if it is possible, just want to know the right way. cheers.

<?php  
      if($_GET["main"]=="add-doc"){
            echo "<script> 
                       var r=confirm(\"Press a button\");
                       if (r==true)
                       {
                           <? require_once(\"doc_add.php\"); ?> <--- PHP here
                       }
                       else
                       {
                           x=\"You pressed Cancel!\";
                       }
                       </script>";
        } 
?>

Answer 1

Technically is there no difference including PHP in HTML or in CSS or in JavaScript. HTML is static. CSS and JavaScript are client side dynamic languages to complement HTML. They add to HTML what PHP or any other server side language can not do server side.

That is why using PHP in JavaScript is considered an anti-pattern. CSS and JavaScript should perform actions that the server side is not able to control. All the information for those actions should therefor be client side. Maintenance is more difficult when the code of JavaScript can be found within a PHP page. Create an .js file instead, make a function call returning what is in doc_add.php and go for it.

Answer 2

if($_GET["main"]=="add-doc"){
    echo "<script>
               var r=confirm(\"Press a button\");
                       if (r==true)
                       {
                           " . require_once('doc_add.php') . "  
                       }
                       else
                       {
                           x=\"You pressed Cancel!\";
                       }
          </script>";
}

Answer 3

Just echo the additional part.

By the way, you could use ' for echo so that you don't have to escape the " in javascript. (Although " and ' quotes in PHP are slightly different, it works functionally in this case.) Or you could use ' inside the javascript.

<?php  
  if($_GET["main"]=="add-doc"){
    echo '<script> 
         var r=confirm("Press a button");
         if (r==true)
         {';
    require_once("doc_add.php");
    // Make sure the file returns valid javascript
    echo '}
         else
         {
             x="You pressed Cancel!";
         }
         </script>';
  }

Answer 4

First you need to understand that PHP is a server-side script, and javascript is a client-side script. This means that once the PHP script finishes rendering the HTML file, it cannot do any more actions.

What you can do, is dynamically render the javascript content before javascript runs.

in your case:

<?php  
      if($_GET["main"]=="add-doc"){ ?>
           <script> 
                       var r=confirm("Press a button");
                       if (r==true)
                       {
                           <? require_once(\"doc_add.php\"); ?>
                       }
                       else
                       {
                           x="You pressed Cancel!";
                       }
                       </script>
           <?php
        } 
?>