how to execute the javascript functionalities from php file-CodePudding

I work on php and javascript. Now I want to call the javascript functionalities in my php code but it is now working. the code of php that execute the javascript code is

echo '<script type="text/javascript">
                    alert( document.getElementById("popup"));
                    document.getElementById("popup").style.display = "block";
                    document.getElementById("popup").classList.toggle("active");
            </script>';

but the alert gives a null value and does not execute the code of html. the code of html is

<div class="popup" id="popup">
                <div class="overlay"></div>
                <div class="content">
                    <!--                    <div class="close-btn" onclick="closePopup()">&times;</div>-->
                    <div class="row">

                        <div  class="col-lg-12 col-md-9  col-sm-12">
                            <img width="200" height="200" src="https://cdn.dribbble.com/users/2469324/screenshots/6538803/comp_3.gif">
                            <h2 id="errorHead">fields are required</h2>
                            <p id="errorMessage">
                                All fields are required. fill all fields
                            </p>
                            <button style="background-color: darkgreen; width: 130px; margin-top: 5%;" class="btn btn-success radiusChange backgroundChange" onclick="closePopup()"> Close</button>
                        </div>
                    </div>
                </div>
            </div>

how I execute this code, basically it is the popup that I want to run. please give the way to solve this problem.

CodePudding user response：

<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>Call JS Code</title>
<?php
echo '<script type="text/javascript">
alert("Execute Javascript Code");
</script>';
?>
</head>
<body>
</body>
</html>

CodePudding user response：

You have to wait for the document to be completely loaded before accessing its nodes.

May you try echoing the following ? You should get the #errorMessage content, ie you are now able to access the popup node and do your stuff

<script type="text/javascript">
  window.onload = () => {
    alert(document.getElementById("popup").querySelector("#errorMessage").innerText);
    //you can deal with the popup node :)
  }; 
</script>