Question

Here is my code: http://jsfiddle.net/9Vvpj/4/

Please help me figure out why this working fine in EVERYTHING other than IE7!

It looks like my variable:

var quantity = quantity_input.val();

is undefined

Answer 1

Don’t use the same ID for different elements. Even in browsers that support it, it’s not how the DOM is supposed to work.

If you use this code to find your input you won’t even need the IDs:

var quantity_input = $(this).parent().siblings(".quantity")

It’s also a good idea to explicitly specify that you’re working with a number:

var quantity = parseInt(quantity_input.val());

Note that this method works when using developer tools to switch to IE7:
http://jsfiddle.net/9Vvpj/5/