pass parameters using variable?

Question

This is a simple syntax question.

I declare a variable:

<script type="text/javascript">
            var id_1= '<?php echo $id; ?>';
    </script>

And then in a externally loaded js file im trying to call a function using the variable (the external js file is loaded after the ^^ variable declaration:

 loadComments(id_1);

The id_1 is being passed literally as 'id_1', not recognizing it should be a variable. What am I doing wrong?

what value does the $id hold in php.. add an alert(id_1); right after assigning the variable... what does it alert ? — Gabriele Petrioli
– Gabriele Petrioli, Commented Jul 11, 2012 at 14:57
Your code should be fine as it stands. Probably it's some kind of scope problem. What is the error message? — Christoph
– Christoph, Commented Jul 11, 2012 at 14:59
can you post the loadComments code ? and do you get an error or just wrong results ? — Gabriele Petrioli
– Gabriele Petrioli, Commented Jul 11, 2012 at 15:00

Bojangles · Accepted Answer · 2012-07-11 14:59:34Z

2

var id_1 = '<?php echo $id; ?>';

Will echo something like this:

var id_1 = '10';

Which is treated as a string in JavaScript. You want to do this instead, so that you assign a number to id_1:

var id_1 = <?php echo $id; ?>;

This will print out something like this:

var id_1 = 10;

answered Jul 11, 2012 at 14:59

Bojangles

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6 Comments

Christoph Over a year ago

Alternatively, keep the quotes and run something like parseInt() in the variable.

Bojangles Over a year ago

@Christoph That would work, but there's no need to do so; if you can assign an integer verbatim, why go through the hassle of casting a string to an integer?

Christoph Over a year ago

For example when $id; can be more then just a number? Then it would throw an error, while keeping the quotes, parsing it and checking for a number would not.

Bojangles Over a year ago

If it is, but you want to assign a number to a JS variable and you have full control over the script that generates $id, then you're doing something wrong if you assign 20foo to id_1.

Christoph Over a year ago

Well, I understand your point, but still these were only implications made from your side and not confirmed by the OP;)

|

Ionel Lupu · Accepted Answer · 2012-07-11 14:56:49Z

1

The php code is recognized only by a .php file.

Put your code in a .php file and run it on you local server

answered Jul 11, 2012 at 14:56

Ionel Lupu

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1 Comment

Jonah Katz Over a year ago

That isnt the problem, the php code is being processed just fine. What the browser sees is var id_q = '2'

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