脚本类型=“ text / javascript”变量无法捕获PHP回显的JSON

Question

I'm working on a PHP web app that retrieves loads of data from a MYSQL database, then uses PHPs json_encode to convert the associative arrays into JSON.

<script type="text/javascript">
    var json = <?php
    // get loads of data from MYSQL database, store in $array
    echo(json_encode($array));
    ?>;
</script>

This appeared to work fine before, but now when pressing F12 in chrome and checking the console, JavaScript throws an error as it doesn't recognize the opening < in the <?php .

I've found that if I remove the type="text/javascript" from the script tag, it reads it fine.

EDIT:

If I use the following, it works:

<script>
    var json = <?php
    // get loads of data from MYSQL database, store in $array
    echo(json_encode($array));
    ?>;
</script>

It seems that adding a type to the script tag prevents PHP from executing prior to it being sent to the client side device.

Why is this?

Answer 1

It appears that the tag can actually be used to run PHP code, if you use:

<script language="php"> echo("hello"); </script>

I assume that setting a type in the script tag makes it only evaluate a single language within the tags - leaving it without a type allows it to stay a multi-language script tag.

Source: http://php.about.com/od/advancedphp/qt/mixed_scripting.htm

Therefore, using something like

<script>
var json = <?php
echo($var);
?>;
</script>

will evaluate both languages (obviously PHP server side), but setting a type or language in the script tag will prevent other languages / types within the tags from being evaluated.