Question

I want to test whether a request parameter is greater then 12 or not JavaScript.

It always gives the alert “lesser” even when I change the value of q to 12.

The current URL is: www.test.com?id=2

How can this be done in JavaScript?

Answer 1

Your code works. If it returns true, then it alerts greater. Although you should be adding semicolons at the end of statements. Your code would look like this:

var q = 14;
if (q > 10)
    alert('greater');
else
    alert('Lesser');

Working demo

As said by Derek, if q === 10, then it would alert ‘Lesser’ because 10 is not more than 10.

EDIT: Here, you have 2 options. Either use something like PHP to make q equal to the number like this:

q = <?php echo $_GET['id']; ?>

Note that using this would open your site up to all kinds of XSS, so if you decide to go this way, learn a bit about security, and don’t rush into uploading it to a live website.

Or, if you want to to do it using JavaScript only, then do it like this:

q = location.href.substring(location.href.indexOf('id=')+3); //3 is the length of id=
q = parseInt(q, 10); //With substring, you get a string, so you have to parse it

The 10 is the radix parameter, avoiding you getting strange numbers for inputs such as 010 (would be 8 without the parameter).