Q:

jQuery - Add to Favourites

I have a loads of reports. Each report as it's own page. When the user is on a page, I want them to be able to add a report to their favourites. I don't mean browser favourites, I mean their favourite reports when they log into the system
Googling this, for obvious reasons, brings back endless tutorials/scripts on how to add to the browser favourites which isn't what I want
I have a button saying "Add to Favourites". When this is clicked, the report should be added. The button should then be removed and replaced with one saying "Remove From Favourite"
I realise ASP/PHP will be needed to do the actual adding/removing but any guidance on how to achieve this would be most helpful.
Would it be something along the lines of
$(function() {
  $('.report_add').click(function() {
    this_id= this.attr("id");
    $.ajax({
      type: 'POST',
      data: 'reportid'+this_id+'=&userid=789',
      success: function() { ... },
      error: function(){ ... },
      url: '/url/',
      cache:false
    });
  });
});

A:

You can change this:
this_id= this.attr("id");

data: 'reportid'+this_id+'=&userid=789',

to this:
var this_id= this.id;

data: 'reportid='+this_id+'&userid=789',

or:
var this_id= $(this).attr("id"); // add a jQuery wrapper

data: 'reportid='+this_id+'&userid=789',

In your code you have two issues  
1. you are not picking the id correctly because you applied jQuery's .attr() method to a dom node instead of jQuery object. so that has to be either this.id or $(this).attr('id').
2. your data string is not well formed:
data: 'reportid'+this_id+'=&userid=789',
//-------------^----------^--------------your '=' sign is at wrong place

instead you can send the values like this:
 data: 'reportid='+this_id+'&userid=789',

or
data: {reportid : this_id, userid : 789},

in your code:
$(function() {
   $('.report_add').click(function() {
     var this_id= this.id; // <---------update this
     $.ajax({
        type: 'POST',
        data: {reportid : this_id, userid : 789}, // <---- and this
        success: function() { ... },
        error: function(){ ... },
        url: '/url/',
        cache:false
     });
  });
});

