Question

95

How to show print_r() content in alert message box?

rated 0 times [ 97] [ 2] / answers: 1 / hits: 17978 / 11 Years ago, wed, may 15, 2013, 12:00:00

I know that whenever I write

$food = array('fruit'=>'apple', 'veggie'=>'tomato', 'bread'=>'wheat');

$text = print_r($food, true);

echo $text;

Output will be:

Array('fruit'=>'apple', 'veggie'=>'tomato', 'bread'=>'wheat')

But when I am trying to display this via alert message box, it does not show anything.

The code for js alert I wrote as follows:

echo <script type='text/javascript'> alert('{$text}') </script>;

This does not work. When I assign a different string to $text then it works. Seems like alert() does not like the format of $test string. If I write in this way:

echo <script type='text/javascript'> alert('Array('fruit'=>'apple', 'veggie'=>'tomato', 'bread'=>'wheat')') </script>;

I get the correct output. So not sure what is wrong there.

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braeden

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3 Years ago

answered 11 Years ago isaacvalentinn · Accepted Answer

To convert PHP array into javascript array you must use json_encode. JSON (JavaScript Object Notation) is a format for data-interchange between programming languages based on the JavaScript. Because JSON is a text format, the result of encoding can be used as a string or as a javascript object.

$food = array('fruit'=>'apple', 'veggie'=>'tomato', 'bread'=>'wheat');



// show the array as string representation of javascript object

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



// show the array as javascript object

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



// show the output of print_r function as a string

$text = print_r($food, true);

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

A few tips for debugging:

for inspection of JavaScript objects, console.log is a very useful

if you want a cleaner print_r output ( on Windows) use:

function print_r2($val){

    echo '<pre>'.print_r($val, true).'</pre>';

}