Echo JavaScript alert of a PHP array value on an HTML button? - Stack Overflow

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I'm trying to use PHP to echo a set of buttons (buy & sell) in a stock trading game. The buttons will eventually have an onclick= event handler that calls a JavaScript function to populate some fields on a form, but I'm just trying to get an alert() with one piece of data to work. I just can't get the results from my echo statement to print the alert correctly, so it doesn't even trigger. I've also used print_r ($stockInfo) to ensure my array is properly filled with test data.

Here's my array:

$stockInfo = array(
    array('name' => 'Company 1', 'description' => 'Description 1', 'price' => '100', 'yield' => '.05'),
    array('name' => 'Company 2', 'description' => 'Description 2', 'price' => '89', 'yield' => '.06'),
    array('name' => 'Company 3', 'description' => 'Description 3', 'price' => '110', 'yield' => '.03')
);

And my PHP code that attempts to generate a button:

<?php
echo <<<EOT
    <button id="buy" class="btn btn-primary btn-small" onclick="alert('$stockInfo[0]["name"]');">Buy</button>
EOT;
?>

The result of that code is:

<button id="buy" class="btn btn-primary btn-small" onclick="alert('Array["name"]');">Buy</button>

I just can't figure out why I can't get even a simple alert to fire. Running:

echo $stockInfo[0]["name"];

Correctly prints out "Company 1", but it doesn't print that text in the argument of the alert().

I've read Stackoverflow, lots of web articles, and experimented for the past day and I just can't figure this out. If anyone can provide any help, I'd GREATLY appreciate it.

Thanks!

I'm trying to use PHP to echo a set of buttons (buy & sell) in a stock trading game. The buttons will eventually have an onclick= event handler that calls a JavaScript function to populate some fields on a form, but I'm just trying to get an alert() with one piece of data to work. I just can't get the results from my echo statement to print the alert correctly, so it doesn't even trigger. I've also used print_r ($stockInfo) to ensure my array is properly filled with test data.

Here's my array:

$stockInfo = array(
    array('name' => 'Company 1', 'description' => 'Description 1', 'price' => '100', 'yield' => '.05'),
    array('name' => 'Company 2', 'description' => 'Description 2', 'price' => '89', 'yield' => '.06'),
    array('name' => 'Company 3', 'description' => 'Description 3', 'price' => '110', 'yield' => '.03')
);

And my PHP code that attempts to generate a button:

<?php
echo <<<EOT
    <button id="buy" class="btn btn-primary btn-small" onclick="alert('$stockInfo[0]["name"]');">Buy</button>
EOT;
?>

The result of that code is:

<button id="buy" class="btn btn-primary btn-small" onclick="alert('Array["name"]');">Buy</button>

I just can't figure out why I can't get even a simple alert to fire. Running:

echo $stockInfo[0]["name"];

Correctly prints out "Company 1", but it doesn't print that text in the argument of the alert().

I've read Stackoverflow, lots of web articles, and experimented for the past day and I just can't figure this out. If anyone can provide any help, I'd GREATLY appreciate it.

Thanks!

• php
• javascript
• echo
• alert
• heredoc

Share Improve this question Follow asked Mar 19, 2012 at 21:21 Kyle CarlsonKyle Carlson 8,17355 gold badges3838 silver badges4444 bronze badges

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3 Answers 3

Sorted by: Reset to default 5

To use variables in heredoc syntax, you have to put curly brackets around them:

<?php
echo <<<EOT
    <button id="buy" class="btn btn-primary btn-small" onclick="alert('{$stockInfo[0]["name"]}');">Buy</button>
EOT;
?>

Ideally, you don't want to put variables directly into your output like that because if there's just a single ' in that string your JavaScript will screw up.

Instead, avoid both problems by not using HEREDOC and using the proper method:

echo "<button id=\"buy\" class=\"...\"
   onclick=\"alert(".htmlspecialchars(json_encode($stockInfo[0]['name'])).");\">Buy</button>";

json_encode essentially makes any PHP variable (except resources) able to be dumped directly into JavaScript code.

htmlspecialchars makes the result safe to use in an HTML attribute.

echo <<<EOT
    <button id="buy" class="btn btn-primary btn-small" onclick="alert({$stockInfo[0]["name"]});">Buy</button>
EOT;
?>

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