How to retrieve $_SESSION value in a JavaScript/HTML - javascript

I have this working script yet when I change it to retrieve(supposedly) the value inside $_SESSION["username"], it doesn't retrieve anything. The whole page is saved as .php as I am using some codes that uses PHP.
Code:
echo "<script type=text/javascript>";
echo "var hidden = false;";
echo "function actiondb1() {";
echo "if(!hidden) {";
echo "document.getElementById(\'clickdb1\').style.visibility = \'hidden\';";
echo "document.getElementById(\'db1\').style.visibility = \'visible\';";
echo "document.getElementById(\'db1\').disabled = false;";
echo "document.getElementById(\'db1\').value =".$_SESSION["username"];.";";
echo "}";
echo "}";
echo "</script>";
How can I make the script to properly retrieve the data inside $_SESSION["username"];?

Observe that, for instance, if the value of $_SESSION["username"] is John, your echo will be generating this result:
document.getElementById('db1').value = John;
But John is supposed to be a string and should be wrapped in quotation marks, otherwise JavaScript will understand it as a variable name (which value will be probably undefined).

As Havenard mentioned, this line is missing Javascript single quotes to properly denote a string variable:
echo "document.getElementById(\'db1\').value ='".$_SESSION["username"];."';";
However, you really shouldn't print JS out with PHP if you can help it. Though iatboy's answer answer won't ultimately fix your bug, it is a much cleaner way of doing things.
?>
<script type=text/javascript>;
var hidden = false;
function actiondb1() {
if(!hidden) {
document.getElementById('clickdb1').style.visibility = 'hidden';
document.getElementById('db1').style.visibility = 'visible';
document.getElementById('db1').disabled = false;
document.getElementById('db1').value ='<?php echo $_SESSION["username"];?>';
}
}
</script>;
<?php

Did you start session in this page?If you didn't,use the follow code to start session.
session_start();
Then change your code to
echo "<script type=text/javascript>";
echo "var hidden = false;\n";
echo "function actiondb1() {\n";
echo "alert('".$_SESSION['username']."')\n"; //test code
echo "if(!hidden) {\n";
echo "document.getElementById('clickdb1').style.visibility = 'hidden';\n";
echo "document.getElementById('db1').style.visibility = 'visible';\n";
echo "document.getElementById('db1').disabled = false;\n";
echo "document.getElementById('db1').value ='".$_SESSION["username"]."';\n";
echo "}\n";
echo "}\n";
echo "</script>";
it will be ok.

Related

define javascript variable from php variable within php code

I am trying to define javascript variable from php variable in the running php code.
Here is my code:
echo "<script>";
echo "var s1 = '<?php echo isset($s1) ? $s1 : '' ?>';";
echo "getAirdrop();";
echo "</script>";
But this code not defining the javascript variable.
You don't need php tags again.
Try it like this:
echo "<script>";
echo "var s1 = '";
echo isset($s1) ? $s1 : '';
echo "';";
echo "getAirdrop();";
echo "</script>";
You can do it in one line, just concatenate all yours echo :
echo "<script> let s1 = ".isset($s1) ? $s1 : ''." getAirdrop(); </script>"

how to pass php variable to javascript?

I am using following code to pass PHP variables to javascript. but it is not working.
function gto(str) {
document.getElementById('goto').action = str;
document.getElementById('ID').value = <?php echo "$userid" ?>;
document.getElementById('name').value = <?php echo "$user_name" ?>;
document.getElementById('gname').value = <?php echo "$usergname" ?>;
document.getElementById('fmname').value = <?php echo "$userfname" ?>;
document.getElementById('img').value = <?php echo "$userimg" ?>;
document.getElementById('email').value = <?php echo "$useremail" ?>;
document.getElementById('goto').submit();
}
Following is the PHP code
<?php
if($_POST["name"] == null)
{
$user_name = 'Annomyous';
}
else{
$user_name = $_POST["name"];
$userid= $_POST["id"];
$usergname= $_POST["gname"];
$userfname= $_POST["fname"];
$userimg= $_POST["img"];
$useremail= $_POST["email"];
}
echo "<p style='color : white'>$user_name";
echo "$userid" ;
echo "$gname";
echo "$fname";
echo "$img";
echo "$email";
echo "$user_name";
echo "$user_name</p>";
$user_name =htmlspecialchars($user_name);
$user_name =str_replace("<script>","", $user_name);
?>
the output is a follows:
ReAlItY TuTs104598758504708047866ReAlItY TuTsReAlItY TuTs//this is php echo output.
JAVASCRIPT OUTPUT:-
function gto(str) {
document .getElementById('goto').action = str;
document.getElementById('ID').value = ;
document.getElementById('name').value = Annomyous;
document.getElementById('gname').value = ;
document.getElementById('fmname').value = ;
document.getElementById('img').value = ;
document.getElementById('email').value = ;
document.getElementById('goto').submit();
}
Function gto is called here:
<button class="w3-btn header-btn" onclick="gto('Contact.php');">Contact Us</button>
I can see in PHP output I am getting all variable output.
but nin juavascript im getting only Annonymous why????
I need to pass post variables to contact us so i am using the form tag and javascript but this is not working Please help me!
Thanks in Advance
values from php to js can be passed in many ways, here's one of them
try to pass the php values when calling the js function, like this:-
<button onclick="gto('Contact.php','<?php echo $userid;?>','<?php echo $username;?>');">Contact Us</button>
and then get values on js function like this:-
function gto(str,userid,username) {
document .getElementById('goto').action = str;
document.getElementById('ID').value = userid;
document.getElementById('name').value =username;
}
that's it, now use the values in js as your wish
Uh, found another issue. The js is in smart quotes, which won't work... "`" is invalid. use "'".
Also, w3schools can't handle php in their editor, so it's no use.
Example for POST requests: https://www.w3schools.com/code/tryit.asp?filename=FQSA8MJYGJ47
Hope this helps.

cant echo javascript alert from php

I've looked for an answer already, but I understand how to achieve an alert from php I just don't know what I am doing wrong on this particular piece of code.
I had this working until I added the if statement.
if ($errors) {
echo "<script type='text/javascript'>";
echo "alert('Records Were Uploaded');";
echo "window.location.href = 'EmployeePicker.php';";
echo "</script>";
} else {
echo "<script type='text/javascript'>";
echo "alert('There was a problem with your file');";
echo "window.location.href = 'csvUpload.php';";
echo "</script>";
}
It worked fine when it was just .
echo "<script type='text/javascript'>";
echo "alert('Records Were Uploaded');";
echo "window.location.href = 'EmployeePicker.php';";
echo "</script>";
If comment everything out and just do
echo "<script type='text/javascript'>";
echo "alert('There was a problem with your file');";
echo "window.location.href = 'csvUpload.php';";
echo "</script>";
this will not work. I'm so confused. It doesn't make sense why the second alert doesn't work.
I forgot to mention, In the if statement from above the first alert will work, it's that second alert that I can't get to fire.
Sorry about the confusion, the $error is a bool. If it is true a filw was uploaded, if false it wasn't.
I think you are doing the opposite of what you want:
Your if case doesn't match the action performed inside.
Maybe you should do:
if (!$errors) {
echo "<script type='text/javascript'>";
echo "alert('Records Were Uploaded');";
echo "window.location.href = 'EmployeePicker.php';";
echo "</script>";
} else {
echo "<script type='text/javascript'>";
echo "alert('There was a problem with your file');";
echo "window.location.href = 'csvUpload.php';";
echo "</script>";
}
and you can also save up on echo words - and make it more readable - doing sth like:
echo <<<HTML
<script type='text/javascript'>
alert('Records Were Uploaded');
window.location.href = 'EmployeePicker.php';
</script>
HTML;
just if you want :)
[EDIT] Note that according to what $errors hold (either integer or array), you can check that there is no error by either !$errors if integer or !count($errors) if array.
[EDIT] Trying your second piece of code as a standalone
If you need to trace what is wrong you need to isolate bit by bit!
first try code 1 as a new php file if it does not alert and redirect on your system then something is wrong in your configs.
If it works something is wrong in your code logic.
I could also run code 2 with no pb by first setting the $errors var to 1 or 0.
code 1
<?php
$errors = 1;
echo "<script type='text/javascript'>";
echo "alert('There was a problem with your file');";
echo "window.location.href = 'csvUpload.php';";
echo "</script>";
?>
code 2
<?php
$errors = 1;
if ($errors) {
echo "<script type='text/javascript'>";
echo "alert('Records Were Uploaded');";
// echo "window.location.href = 'EmployeePicker.php';";
echo "</script>";
} else {
echo "<script type='text/javascript'>";
echo "alert('There was a problem with your file');";
// echo "window.location.href = 'csvUpload.php';";
echo "</script>";
}
?>
And about your $errors var, if true means no error you should definitely rename it to sth less tricky like $uploadSuccessful. ;)
It should echo out good. Try checking your php error log file to see if there are any clues as to the issue in there.
Just a small most like likely personal preference of mine that may help you is to separate out the logic a bit. Please see below.
<?php
// STATUS
$errors = true;
// OUTPUTS
$upload_success = "<script type='text/javascript'>";
$upload_success .= "alert('Records Were Uploaded');";
$upload_success .= "window.location.href = 'EmployeePicker.php';";
$upload_success .= "</script>";
$upload_fail = "<script type='text/javascript'>";
$upload_fail .= "alert('There was a problem with your file');";
$upload_fail .= "window.location.href = 'csvUpload.php';";
$upload_fail .= "</script>";
//LOGIC
if ($errors) {
echo $upload_success;
} else {
echo $upload_fail;
}
?>

Passing javascript array via POST to PHP does not working

I need to pass a javascript array, via POST, to a PHP file.
I've tried to semplify my original business trying to explain my troubles ...
This is my first PHP file, in which I declare a javascript array and I set each element to 1 value (not a great business I know, but it doesn't matter, it's only to explain ....)
<?php
echo '<form action="testPhp-2.php" method="POST" target="testPhp-2">';
echo '<script type="text/javascript">';
echo 'var arr_selections = [];';
echo 'for(i=0; i < 10; i++)';
echo ' {';
echo ' arr_selections[i] = 1';
echo ' }';
echo 'arr_selections_json = JSON.stringify(arr_selections);';
echo 'alert (arr_selections[2]);';
echo 'document.write("<br/>");';
echo ' ';
// echo 'document.write("<input type="hidden" />");';
echo 'document.write("<input type=\"hidden\" name=\"arr_selections_json\" value=\"arr_selections_json\" />");';
echo ' ';
echo '</script>';
echo ' <input type="submit" value="Controlla">';
echo ' </form>';
?>
.... and here you are the code of testPhp-2 file ...
<?php
if(isset($_POST['arr_selections_json']))
{
echo "OK, array exist !! ";
echo '</br>';
echo '</br>';
$arr_selections = json_decode($_POST['arr_selections_json'], true);
echo $arr_selections[0];
}
else {
echo "NO; array does not exist !! ";
echo '</br>';
echo '</br>';
}
?>
Now, if you try to execute the code you'll see the OK, array exist !! message but no array value is printed about the echo $arr_selections[0]; line of code in testPhp-2.php file.
Any suggestion will be appreciated! Thank you in advance!
Cesare
Problem is that you're setting the value of the input to the litteral string "arr_selections_json" instead of to the contents of that variable.
Change
echo 'document.write("... value=\"arr_selections_json\" />");';
To
echo 'document.write("... value=\""+arr_selections_json+"\" />");';

Referencing a defined html variable in JS

My index.php page includes a config.php file, which returns an array that I have defined some variables in by using "define('var1' , 10)".
I am trying to validate my forms input, but I can't figure out how I can reference var1 from within the JS function. What is the easiest way to do this?
Just echo it to a javascript variable:
<script type="text/javascript">
var var1JS = "<?php echo $var1; ?>";
</script>
Not quite sure I am full understanding without seeing the code but, you could echo the variable from the PHP array in the JS function (as above answer).
Or Echo the entire JS query:
$y = count($PHPdata_array);
echo "function exampleFunction() {";
echo "var ArrayName = [";
for ($i = 1; $i <= $y; $i+=2) {
echo "{" . $PHPdata_array[$i] . "," . $PHPdata_array[$i-1] . "},";
}
echo "];";

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