PHP echo javascript doesnt work in if statement

Question

So the code looks like this:

<script>
function createFolder(folder){
    $.ajax({
    url: "index.php",
    type: "POST",
    data: {'folder':folder},
    success: function(data) {
        console.log("successful post");
        }
    });
}
</script>

<?php
if(isset($_POST["folder"])){
    $folder = $_POST["folder"];
    if(!file_exists($folder)) {
        mkdir($folder);                         <--- this code runs
        echo '<script>alert("qwe")</script>';   <--- this code doesnt run 
    }
    else {
        echo '<script>alert("qwer")</script>';  <--- this code doesnt run
    }
    echo '<script>alert("qwert")</script>';     <--- this code doesnt run 
}
echo '<script>alert("qwerty")</script>';        <--- this code runs
?>

..so in the if-statement where I check the file exists the echo doesnt work, but the mkdir($folder) command runs successfully and it is a bit confusing for me. Why echo doesnt work if it in an if-statement?

Do the other alerts work? – B''H Bi'ezras -- Boruch Hashem Aug 18 '20 at 00:51 — B''H Bi'ezras -- Boruch Hashem, Aug 18 '20 at 00:51

score 2 · Answer 1 · answered Aug 18 '20 at 00:54

2

The <script> tags will only be executed if you put them into the HTML of a DOM element. That doesn't happen automatically, you need to do it in your success function.

function createFolder(folder){
    $.ajax({
        url: "index.php",
        type: "POST",
        data: {'folder':folder},
        success: function(data) {
            console.log("successful post");
            $("#somediv").html(data);
        }
    });
}

answered Aug 18 '20 at 00:54

Barmar

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That will set the content of the div to the entire page he's in plus the additional echoes – B''H Bi'ezras -- Boruch Hashem Aug 18 '20 at 01:02
@bluejayke Only if it script echoes the entire page even when it's called by an AJAX request. – Barmar Aug 18 '20 at 02:54

B''H Bi'ezras -- Boruch Hashem · Accepted Answer · 2020-08-18T04:49:41.943

0

Ok you're trying to get the value from a php server using Ajax with JavaScript, then I'm guessing you want to alert to the page when received

The problem is that

if(isset($_POST["folder"]))

Only is true in the actual Ajax request itself, which only fetches the data as a string from the server, but doesn't actually execute it

If you want the code to be executed on the page, you have to do that on the Ajax on success call on the client side, so

<script>
function createFolder(folder){
    $.ajax({
    url: "index.php",
    type: "POST",
    data: {'folder':folder},
    success: function(data) {
        document.body.innerHTML+=data
         // Or maybe data.responseTezt or something idk 
        // Look up in the API how to get the text content
        console.log("successful post");
        }
    });
}
</script>

Then on the server side only echo the JavaScript if "folder" is not set,

Also in the client side in order to actually execute you JavaScript you may have to make a new Dom parser

so the whole php file is basically

<?php
if(isset($_POST["folder"])) {
    //All of your other code
} else {

?>
<!--all of your HTML code-->
<script>
function createFolder(folder){
    $.ajax({
    url: "index.php",
    type: "POST",
    data: {'folder':folder},
    success: function(data) {

      
         // Or maybe data.responseTezt or something idk 
        // Look up in the API how to get the text content
        var dp= new DOMParser()
        var doc=dp.parseFromString(data,"text/html")
        Array.from(doc.children).forEach(t=>
            document.body.appendChild(t)
        )
  
        console.log("successful post");
        }
    });
}
</script>
<?php } ?>

edited Aug 18 '20 at 04:49

answered Aug 18 '20 at 00:55

B''H Bi'ezras -- Boruch Hashem

3,665
3
33
83

JavaScript isn't executed when assigning to `innerHTML`. – Barmar Aug 18 '20 at 02:53
@barmar true sometimes happens, might have to make a DOMParser, loop through the new documents elements and add them to the body one at a time (in the loop) – B''H Bi'ezras -- Boruch Hashem Aug 18 '20 at 04:47
See https://stackoverflow.com/questions/1197575/can-scripts-be-inserted-with-innerhtml?noredirect=1&lq=1 – Barmar Aug 18 '20 at 05:00
@barmar ya you could eval the specific JavaScript too but if a bunch of html is echoed back together with JavaScript I think Dom parser is the only way – B''H Bi'ezras -- Boruch Hashem Aug 18 '20 at 20:48
"Ok you're trying to get the value from a php server using Ajax with JavaScript, then I'm guessing you want to alert to the page when received" Well, no. I want to alert to the page when the mkdir was successful or when it wasnt (because the dir is already created or it has invalid name) – kreestyahn Aug 19 '20 at 12:48
@kreestyahn so basically you want to activate a JavaScript function only when a server side operation, which is unconnected to input from Ajax, is completed? – B''H Bi'ezras -- Boruch Hashem Aug 19 '20 at 12:50

PHP echo javascript doesnt work in if statement

2 Answers2