• Home
  • Recent Q&A
  • Java
  • Cloud
  • JavaScript
  • Python
  • SQL
  • PHP
  • HTML
  • C++
  • Data Science
  • DBMS
  • Devops
  • Hadoop
  • Machine Learning
in PHP by
Q:
How to call a JavaScript function from PHP?

How to call a JavaScript function from PHP?

<?php

  jsfunction();

  // or

  echo(jsfunction());

  // or

  // Anything else?

The following code is from xyz.html (on a button click) it calls a wait() in an external xyz.js. This wait() calls wait.php.

function wait()

{

  xmlhttp=GetXmlHttpObject();

  var url="wait.php"; \

  xmlhttp.onreadystatechange=statechanged;

  xmlhttp.open("GET", url, true);

  xmlhttp.send(null);

function statechanged()

{

  if(xmlhttp.readyState==4) {

       document.getElementById("txt").innerHTML=xmlhttp.responseText;

  }

}

and wait.php

<?php echo "<script> loadxml(); </script>";

where loadxml() calls code from another PHP file the same way.

The loadxml() is working fine otherwise, but it is not being called the way I want it.

1 Answer

0 votes
by

As far as PHP is concerned (or really, a web server in general), an HTML page is nothing more complicated than a big string.

All the fancy work you can do with language like PHP - reading from databases and web services and all that - the ultimate end goal is the exact same basic principle: generate a string of HTML*.

Your big HTML string doesn't become anything more special than that until it's loaded by a web browser. Once a browser loads the page, then all the other magic happens - layout, box model stuff, DOM generation, and many other things, including JavaScript execution.

So, you don't "call JavaScript from PHP", you "include a JavaScript function call in your output".

There are many ways to do this, but here are a couple.

Using just PHP:

echo '<script type="text/javascript">',

     'jsfunction();',

     '</script>'

;

Escaping from php mode to direct output mode:

<?php

    // some php stuff

?>

<script type="text/javascript">

    jsFunction();

</script>

Related questions

0 votes
asked Mar 19, 2020 in PHP by DavidAnderson
0 votes
asked Jun 6, 2020 in PHP by SakshiSharma
...