How many characters allowed in an alert box in JavaScript

Question

Does anyone know what is the maximum number of characters you can display in an alert box?

I'm returning an error alert to the user with details for each of the errors and warnings but apparently the box just don't show up anymore when there is too much data. Here's some of my code:

<?php
    //Two arrays are created in php, one with the errors, one with the warnings.
?>

<script type="text/javascript">
    alert("<?php
         if(count($err) != 0){
             $errorfound = True;
             echo 'Error:\n\n';
             foreach($err as $message){
                 echo '\t' . $message . '\n';
             }
         }
         if(count($warn) != 0){
             echo '\n\nWarning:\n\n';
             foreach($warn as $mess){
                 echo '\t' . $mess . '\n';
             }
        }?>");
</script>

<?php
    //app continues if no error was found
?>

After investigation, my problem didn't come from the capacity of the alert box but was in fact that I needed to addslashes() to my messages (that's why I thought it was working with fewer values, but in fact I was just lucky because they weren't characters that needed to be escaped). I'll definitely change that alert box for something more appropriated, just wanted to say that there is no problem with the alert box.

Answer 1

Personally I despise popup alerts. You might consider using a message box built into the page that can hold an indefinite amount of content, and can be "flashed" on the screen for a few seconds on error.

You can optionally disable the entire page and make the message an overlay. Prototype or jQuery would make quick work of either task.

If you want to see an example of disabling the page, this article uses a progress indicator that could easily be swapped for a message. http://edwardawebb.com/web-development/cakephp/disable-page-show-translucent-progress-bar