Update Profile Field from other Pages

So I am trying to make an automatic currency system where when members do certain things it'll change the amount of currency they have. Basically I have a number field setup on their profiles that's editable by the members but not visible. I want to then be able to grab that info and when they are on other pages and say click a button then it updates their number like + or - a certain amount from their current and then saves that. I've already got the proper coding to put their amount of currency in the nav bar I have setup on every page but the only issue is being able to edit it and have it actually save. I can usually figure stuff out if someone even provides just some kind of code, I feel like I'm missing something to make it into a form to be able to submit/save the info...

Here's what I've got:

Code:

<span id="your_div_id_points1"></span>
      <script>$('#your_div_id_points1').load('/u' + _userdata.user_id + '  #field_id1')</script>