How can I generate Dynamic Javascript?

Question

I render a page using YUI. and depending on the user I need to change how it is rendered. This change is not something that can be parametrized, it is drastic and different for each user.

Please tell me how can I generate Javascript dynamically?

Answer 1

I personally use a PHP file to pass a JavaScript object made up of some basic session and internal settings, nothing mission-critical as passing information to the client isn't overly secure, but I believe it might follow the same principles as what you are looking for.

Similarly, I use this to display certain elements once the client is logged in, although all the authorization is still done on the server-side. If my session handler gives the PHP file the ok, it outputs a JavaScript object using a PHP heredoc string, otherwise, it doesn't output anything. You can use attributes of this object to compare against, or you could output only the JavaScript for how a certain page should be rendered, based on settings in your PHP file.

HTML:

<script src="common/javascript/php_feeder.php" type="text/javascript"></script>

PHP:

//my session handler authorisation check has been removed
//although you could place your own up here.

//assuming session was authorised
//set content type header
header("content-type: application/x-javascript"); 

$js_object = <<<EOT
var my_object = {
    my_attr: '{$my_attr}',
    my_attr2: '{$my_arrt2}',
    etc: '{$etc}'
}
EOT;

print($js_object);

Answer 2

You can probably create two separate Java script files, and include the required file, depending upon the user type.

Pseudocode

If user_type is One
    <Script src='one.js' type='javascript'></script>
else
    <Script src='other.js' type='javascript'></script>
End If

Answer 3

JavaScript has an eval function, so I think (I haven't tried it) that you can generate JavaScript by writing it into a string variable (and then calling eval on that string variable).

Answer 4

A little bit of elaboration here would most certainly help in getting you a more descript and helpful answer. That in mind, though, you could easily just use functions declared inside an if statement to provide distinctly varied experiences for different users.

A very basic example:

<script>
function do_something(userType)
 {
if (userType == 'A')
 {
// everything you need to do for userType A
 }
if (userType == 'B')
 {
// everything you need to do for userType B
 }
 }
</script>