Creating a javascript alert with php that has a php variable inside?

Question

I'm making a form that is supposed to create a javascript alert when some fields aren't filled out or filled out properly. I want to be able to take the error messages I've put in a php variable and display them in the javascript alert window.

The following code does not work:

function died($error) {
    echo '<script type="text/javascript"> alert('.$error.')</script>';
    die();
}

How can I add the string contained in $error between the two "script" strings so it will output properly as a javascript alert?

Thank you!

Solution 1

You only forgot quotations that are required for the JavaScript alert.

If you passed 'hello' to the function, your current code would create alert as:

alert(hello)

instead of doing:

alert("hello")

Therefore, change your line to the following (two double quotes are added before and after concatenating $error):

echo '<script type="text/javascript">alert("'.$error.'");</script>';

and you can use your function:

died('error on whatever');

Solution 2

Display variable php in alert javascript

   <?php 
          function died($error) { ?>

            <script>alert("<?php echo $error; ?>")</script>

    <?php   die(); 
          } ?>

Solution 3

You can use function follow this:

function died($error) {
    echo '<script> alert("'.$error.'")</script>';
    die();
}

Comments

[MarvinLazer]

Thanks! It works, although I don't really understand why. What if I wanted to add other text in the alert that would be concatenated with the variable? Would I have to do something like this? echo '<script>alert('.'Here is some other text!\\n"'.$error.'");</script>';

[user1978142]

as @frankgorman clearly stated, what happens is that, after you concatenated, you missed the quotes inside rendering the error on javascript. If you want to add, just concatenate another string on $error. Example: $error = "Another Line \n" . $error

[Eon]

You know you are very new to a language when you look for ways to alert/log variables :) (happens that I came to search for this answer too)

[Scarl]

This displays nothing. As in it does not display the php variable's value for some reason

[Crickets]

Your answer did not work for me, but this did: echo '<script>alert("' . $str . '");</script>'; -source

[Giovanni Esposito]

Ciao, try to add a small explanation. Code-only answer discourages.