Hi jQuery mobile,

For school I have to make a exercise using jQuery mobile, now I'm going really hard for somebody that isn't into programming at all. But I have two functions I need to use into my exercise and I can't figger it out. 

First about my exercise, I have to make a jQuery mobile site about food and recipes, the goal of the mobile site is that you can select a recipe and tell it how much persons you're going to make it for. After that you will see how much you need of every ingredient and you can click/tick on the boxes if you got the ingredient in your supermarket cart.

1. Fade in/out box/opacity from 100 to like 50%

I have some boxes with the ingredients of the recipe. What the boxes have to do is when you click/tick on it they will like going to opacity 50%. (It's a little bit like the Wunderlist idea, so when you click/tick on a box it will fade a bit away). But there must be a option when you tick it again the opacity will be going to 100% again.

2. Calculation

The quantity have to change when you select more/less persons, but how can I link the box with the number of persons with the boxes of the ingredients quantity. And how can I make the box of persons with +/- function?

If it's not clear, let me know and I will try to explain it better.

Already thanks!

Greetings,

JanPipo