如何在PHP echo中使用JavaScript .value

Question

I got a question to a JavaScript code. I got an HTML form:

<form action="getValue.php" method="post" id="myform">
    <input type="text" id="mybox" name="mybox" />
    <input type="submit" id="submit" name="submit" value="Submit" />
</form>

I want to alert the value by clicking submit button. For this I use this code:

$(document).ready(function(){
    $('#myform').submit(function(event){
        alert(document.getElementById('mybox').value);
    });
});

If I type in for example "123" it alerts "123". Okay, this works. Now I want to run this JavaScript code in PHP echo . For this I tried this:

if(isset($_POST['submit'])){
    echo "<script>alert(document.getElementById('mybox').value);</script>";
}

If I now type in "123" it returns " ". So nothing returns. Can someone explain me why this is or how to fix this?

Cheers

EDIT: It is all in the same file (getValue.php)

Answer 1

Your text box will not be populated when the page has been reloaded.

Try echo'ing the actual post value.

if(isset($_POST['submit'])){
    echo "<script>alert('" . $_POST['mybox'] . "');</script>";
}

Edit:

As you pointed out that you were new to PHP & JavaScript I thought I'd mention that you seem to be using half jQuery and half non-jQuery...

For example instead of using

document.getElementById('mybox').value

You can use

$('#mybox').val();

Answer 2

echo '<script type="text/javascript">alert("Data has been submitted to ' . $_POST['mybox'] . '");</script>';