Javascript hide in php

Question

<?php 
    if( isset($_GET['message']) ) {
        $message = urldecode($_GET['message']);
        echo "<h2 id='mydivm'>". $message . "</h2>";
?>
    <script>
        setTimeout( function() {
            getElementById(mydivm).value='';
            // the alert is working
            alert("hello"); 
        }, 5000);
    </script>
<?php  
    } 
?>

I am trying to hide the $message after 5 seconds through #mydivm. However I can't get regular JavaScript to work or jQuery. Alert works when it is alone. I also have tinymic, but I don't think that is interfering. I have tried putting it outside the PHP

setTimeout(fade_out, 5000);

function fade_out() {
    $("#mydivm").fadeOut().empty();
}

Answer 1

getElementById is a method of the document. Also, you're not passing it a string. You need to change your code from this:

getElementById(mydivm).value='';

to this:

document.getElementById('mydivm').value='';

EDIT: Looking closer, setting the value attribute is not the correct way to do that either. You would need:

document.getElementById('mydivm').innerHTML='';

or better yet:

document.getElementById('mydivm').style.display='none';

Answer 2

Maybe this is not where the error is coming from, but getElementById is a function that belongs to the document object. Most likely, what's happening is that you're receiving a "undefined function getElementById" which you are not seeing. Use it this way:

document.getElementById('mydivm').value = '';