How to call JavaScript function from PHP then act on return value

Question

I am creating a simple discussion forum, where users can create posts, reply to posts, delete posts, etc. I am having some trouble with deleting posts. I can write the PHP to delete the posts fine, but at the moment the post is instantly deleted (so if someone clicks accidently they have no opportunity to cancel). What I want to do is call a JavaScript function to display a confirm box from PHP, then if the function returns true delete the post, otherwise do nothing. In pseudocode, what I want to do is:

<?php

function display_javascript_confirm_box()
{
if(call_javascript_function()==true)
{
delete();//call PHP function to delete post
}
else
{
return false;
//do nothing
} 
}
?>

You have it backwards. Javascript will need to trigger a confirmation and afterwards a new HTTP request if affirmative. See [Reference: Why does the PHP code in my Javascript not work?](http://stackoverflow.com/questions/13840429/reference-why-does-the-php-code-in-my-javascript-not-work) — deceze, Apr 18 '13 at 09:41

score 2 · Answer 1 · answered Apr 18 '13 at 09:41

2

You simply need this

<input type="submit" value="Delete" onclick="return confirm('Your Message');" />

Demo

answered Apr 18 '13 at 09:41

Mr. Alien

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score 2 · Accepted Answer · answered Apr 18 '13 at 09:45

2

The easiest way is to do otherwise: confirm via js, and delete via php )

<a href="/path/to/delete" onclick="return confirm('Do you really want to delete?');">delete</a>

Link will be folowed only if user confirms ok in dialog box.

answered Apr 18 '13 at 09:45

Roman Usachev

296
2
4

Thank you! That looks pretty good, I will try it – imulsion Apr 18 '13 at 09:48

score 1 · Answer 3 · answered Apr 18 '13 at 09:41

1

It is impossible to call a javascript function from PHP. Note that PHP is running on server while javascript is running in the client - the browser

answered Apr 18 '13 at 09:41

hek2mgl

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score 0 · Answer 4 · answered Apr 18 '13 at 09:41

0

Display the confirm box with Javascript, not with PHP. So after it's confirmed, the value of the posted button will be sent to PHP, then you can catch it by isset() and afterwards trigger delete()

answered Apr 18 '13 at 09:41

Royal Bg

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score 0 · Answer 5 · answered Apr 18 '13 at 09:42

0

you should understand that JavaScript runs on a client side (Browser) and PHO on the Server side - if you wants to run some PHP code from javaScript you should establish connection to server. For example using AJAX.

answered Apr 18 '13 at 09:42

Ilya

169
6

How to call JavaScript function from PHP then act on return value

5 Answers5